Large Molecular Hyperpolarizabilities Research Articles

Synthesis, crystal growth, characterization and DFT investigation of a nonlinear optically active cuminaldehyde derivative hydrazone.

Single crystals of (E)-N'-(4-isopropylbenzylidene)isonicotinohydrazide monohydrate (IBIHM) were grown from ethanol by the slow evaporation from solution growth technique at room temperature. The structure was elucidated by single-crystal X-ray diffraction analysis and crystallized in the orthorhombic system with noncentrosymmetric space group P212121. Optical studies reveal that the absorption was minimum in the visible region and the band-gap energy was estimated using the Kubelka-Munk algorithm. The functional groups were identified by Fourier transform infrared spectral analysis. A scanning electron microscopy study revealed the surface morphology of the grown crystal. Investigation of the intermolecular interactions, crystal packing using Hirshfeld surface analysis and single-crystal X-ray diffraction confirm that the close contacts were associated with molecular interactions. Fingerprint plots of Hirshfeld surfaces are used to locate and analyze the percentage of hydrogen-bonding interactions. The second-harmonic generation efficiency of the grown specimen was superior to that of the reference material, potassium dihydrogen phosphate. The grown crystals were further characterized by mass spectrometry and elemental analysis. Theoretical studies using density functional theory (DFT) greatly substantiated the experimental observations. Large first-order molecular hyperpolarizability (β) of about ∼70× was observed for IBIHM. The efficiency of IBIHM in terms of nonlinear optical response was verified and the molecule displayed greater chemical stability and reactivity.

Nonresonant and Resonant Surface-Enhanced Raman Scattering of N-Ethyl-N-(2-hydroxyethyl)-4-(4-nitrophenylazo) Aniline in Poly(methyl methacrylate) on Ag Films with Surface Roughness

Abstract Nonresonant and resonant surface-enhanced Raman scatterings (SERS and SERRS) were studied for N-ethyl-N-(2-hydroxyethyl)-4-(4-nitrophenylazo) aniline (Disperse Red 1, or DR1) in poly (methyl methacrylate) on Ag films with surface roughness. DR1 is a chromophore that consists of azobenzene bridged between electron-donating amine and electron-accepting nitro groups, and it has attracted great attention because of its large molecular hyperpolarizability. DR1 hybridized with metal nanoparticles or nanostructures is promising as a building block for nonlinear plasmonics. Our experimental results demonstrated that the Raman cross sections were highly enhanced both at the molecular nonresonant and resonant excitation wavelengths. The spectroscopic properties of SERRS were taken from resonant Raman (RR), and the enhanced RR cross sections were attributed to electromagnetic enhancements due to surface plasmons (SP). The SERS spectrum was also similar to the RR spectrum, rather than the non-resonant Raman (NR) spectrum, even at the molecular non-resonant excitations. A diagram of energy levels was drawn for the DR1/Ag interfaces by using ultraviolet-visible linear absorption and ultraviolet photoelectron spectroscopic data. The enhanced NR cross sections were explained in terms of the electromagnetic enhancements, as well as the metal-to-molecular charge-transfer, by using the energy diagram.

ABAB Homoleptic Bis(phthalocyaninato)lanthanide(III) Complexes: Original Octupolar Design Leading to Giant Quadratic Hyperpolarizability

The octupolar cube, a Td symmetry cube presenting alternating charges at its corners, is the generic point charge template of any octupolar molecule. So far, transposition into real molecular structures has yet to be achieved. We report here a first step toward the elaboration of fully cubic octupolar architectures. A series of octupolar bis(2,3,16,17-tetra(hexylthio)phthalocyaninato)lanthanide double-decker complexes [Pc2Ln], Ln = Nd (1), Eu (2), Dy (3), Y (4), and Lu (5), are described, whose original three-dimensional structures display the required alternation of ABAB type for one face of the cube and the delocalization between the two rings approximating to the electronic interaction along the edges of the cube. Synthesis, X-ray crystal structure, and study of the optical properties and of the first molecular hyperpolarizability β are reported. The size of the lanthanide (III) central ion modulates the ring-to-ring distance and the degree of coupling between the two phthalocyanine rings. As a consequence, the optical properties of these octupolar chromophores and in particular the strong near-infrared absorption due to the intervalence transition between the two rings also depend on the central lanthanide (III) ion. The first oxidized and reduced states of the complexes, while keeping a similar octupolar structure, display considerably changed optical properties compared to the neutral states. Second-order nonlinear properties were determined by nonpolarized harmonic light scattering in solution at 1907 nm. Exceptionally large dynamic molecular first hyperpolarizabilities √(<βHLS(2)>1907), among the highest ever reported, were found that showed a strong dependence on the number of 4f electrons.

Nonplanar Donor–Acceptor Chiral Molecules with Large Second-Order Optical Nonlinearities: 1,1,4,4-Tetracyanobuta-1,3-diene Derivatives

We have investigated the chiroptical, linear, and second-order nonlinear optical (NLO) properties of five 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) derivatives and elucidated structure-property relationships from the micromechanism. The experimental UV-vis absorption and circular dichroism (CD) spectra were well reproduced by our calculations at TDB3LYP/6-31+G* level of theory. The electron transition property and chiroptical origin have been assigned and analyzed. The results show that the studied compounds possess large molecular first hyperpolarizabilities, especially for compound 5 which has a value of 35 × 10(-30) esu, which is comparable with the measured value for highly π-delocalized phenyliminomethyl ferrocene complex and about 200 times larger than the average first hyperpolarizability of the organic urea molecule. Despite the nonplanarity of these compounds, efficient intramolecular charge transfer (CT) from electron donor to electron acceptor moieties was observed, which plays the key role in determining the NLO response. The intramolecular charge transfer cooperativity was also probed. In view of the first hyperpolarizability values, intrinsic noncentrosymmetric electronic structure, and high stability, the studied compounds have the possibility to be excellent second-order NLO materials.

Synthesis and third-order optical nonlinearities of hyperbranched metal phthalocyanines

A series of novel organic hyperbranched metal phthalocyanines (HMePcs) oligomers were synthesized for investigating their third-order nonlinear optical (NLO) properties. The third-order NLO coefficient was measured by Z-scan technique with a pulsed Q-switched Nd:YAG nanosecond laser at 532nm. The HMePcs showed large molecular cubic hyperpolarizabilities (γ) whose values were of the order of 10−29esu. The variation of substituent groups of and center metal of HMePcs influenced the third-order optical nonlinearity. The presence of electron-withdrawing substituents-fluoro in the phthalocyanine brings about a noticeable improvement of the third-order nonlinear susceptibility χ(3) in these systems and the third-order nonlinear susceptibility χ(3) values of different metal hyperbranched metal (Cu, Ni, Co) phthalocanines oligomers were found to decrease in the order HCuPc>HNiPc>HCoPc.

New acentric quinolinium crystal with high order parameter for nonlinear optical and electro-optic applications

We have designed and synthesized a new, highly efficient electro-optic vanillin-based quinolinium crystal. The HMQ-NS (2-(4-hydroxy-3-methoxystyryl)-1-methylquinolinium naphthalene-2-sulfonate) crystals exhibit an acentric monoclinic space group symmetry Pn with a large effective molecular hyperpolarizability in the crystal with the diagonal component βeff333 = 149 × 10−30 esu, which is comparable to that of benchmark ionic stilbazolium crystals, and a good thermal stability. Therefore, the newly developed HMQ-NS crystal is an attractive candidate for nonlinear optical and electro-optic applications.

Chiroptical, linear, and second-order nonlinear optical properties of binaphthol derivatives

We have investigated the chiroptical, linear, and second-order nonlinear optical (NLO) properties of seven binaphthol derivatives and elucidated structure-property relationships from the micromechanism for the first time. The excitation energies, oscillator strengths, and rotational strengths of the 150 lowest energy electron excitations for the most stable conformers have been calculated at TDB3LYP/cc-pVDZ level of theory. The experimental UV-vis absorption energies were reproduced well by our calculations. The simulated circular dichroism (CD) spectra and calculated optical rotation (OR) values are in reasonable agreement with experimental ones. These results demonstrate that TDDFT calculations can not only describe the electron transition property but also can be used to assign the absolute configurations (ACs) of binaphthol derivatives with high confidence. Whereas OR values are more sensitive to the molecular structures than CD spectra. The electron transition property and chiroptical origin have been assigned and analyzed. These derivatives possess remarkably large molecular first hyperpolarizabilities, especially compound 7 which has a value of 241.65 × 10(-30) esu. This value is about 60 times as large as that of highly π-delocalized phenyliminomethyl ferrocene complex. Moreover, compound 6 exhibits pronounced different second-order NLO response values from neutral state to the two cationic states (6(2+) and 6(4+)), which indicates that this compound could act as a potential NLO switch material. The cooperativity of intramolecular charge transfer of the studied compounds was also discussed.

Theoretical investigation on redox‐switchable second‐order nonlinear optical responses of push–pull Cp*CoEt2C2B4H3‐expanded (metallo)porphyrins

The second-order nonlinear optical (NLO) properties of the Cp*Co(C(2)H(5))(2)C(2)B(4)H(3)-expanded (metallo)porphyrins (Cp* = C(5)Me(5)) have been investigated by using ab inito RHF and density functional theory (DFT) methods. The investigation shows that the compound with expand porphyrin possesses remarkable large molecular hyperpolarizability β(tot) value, ~414.1 × 10(-30) esu (at LC-ωPBE level), and might be an excellent second-order NLO material. From the character of charge transfer (CT) transition, it indicates that the -Cp*Co(C(2)H(5))(2)C(2)B(4)H(3) acts as an electron donor in this kind of systems. As a result of the redox behavior on expanded (metallo)porphyrin, the redox switching character of the NLO responses for the systems 2a-4a has also been studied. The results show that the β(tot) values of reduced forms are larger than that of neutral ones. Furthermore, the time-dependent DFT calculation illustrates that reduced forms have a significant difference on the CT patterns versus neutral ones. The present investigation provides insight into the comparison with DFT results on estimating first hyperpolarizability and the NLO properties of the series of push-pull compounds.

The third-order optical nonlinearities of thiophene-bearing phthalocyanines studied by Z-scan technique

The third-order optical nonlinearities of thiophene-bearing phthalocyanines (Ni-TPc and Cu-TPc) measured using Z-scan technique at 532nm have three features: firstly, both Ni-TPc and Cu-TPc showed large molecular cubic hyperpolarizabilities γ whose values were of the order of 10−30esu; secondly, the nonlinear absorption and the nonlinear refraction contribute almost equally to their molecular cubic hyperpolarizabilities, while for our previous studied phthalocyanines, the contribution from nonlinear refraction was always overwhelming; thirdly, the γ value of Cu-TPc is 1.5 times larger than that of Ni-TPc, which is mainly due to their different nonlinear absorptions. This study may indicate that the incorporation of thiophene rings into phthalocyanines could notably increase the multi-photon absorption cross-section of Pc.

Slow Relaxation of the Magnetization in Non-Linear Optical Active Layered Mixed Metal Oxalate Chains

New Co(II) members of the family of multifunctional materials of general formula [DAMS](4)[M(2)Co(C(2)O(4))(6)]·2DAMBA·2H(2)O (M(III) = Rh, Fe, Cr; DAMBA = para-dimethylaminobenzaldehyde and [DAMS(+)] = trans-4-(4-dimethylaminostyryl)-1-methylpyridinium) have been isolated and characterized. Such new hybrid mixed metal oxalates are isostructural with the previously investigated containing Zn(II), Mn(II), and Ni(II). This allows to preserve the exceptional second harmonic generation (SHG) activity, due to both the large molecular quadratic hyperpolarizability of [DAMS(+)] and the efficiency of the crystalline network which organizes [DAMS(+)] into head-to-tail arranged J-type aggregates, and to further tune the magnetic properties. In particular, the magnetic data of the Rh(III) derivative demonstrate that high spin octacoordinated Co(II) centers behave very similarly to the hexacoordinated Co(II) ones, being dominated by a large orbital contribution. The Cr(III) derivative is characterized by ferromagnetic Cr(III)-Co(II) interactions. Most relevantly, the Fe(III) compound is characterized by a moderate antiferromagnetic interaction between Fe(III) and Co(II), resulting in a ferrimagnetic like structure. Its low temperature dynamic magnetic properties were found to follow a thermally activated behavior (τ(0) = 8.6 × 10(-11) s and ΔE = 21.4 K) and make this a candidate for the second oxalate-based single chain magnet (SCM) reported up to date, a property which in this case is coupled to the second order non linear optical (NLO) ones.

Effect of modified donor units on molecular hyperpolarizability of thienyl-vinylene nonlinear optical chromophores

Highly efficient and thermally stable nonlinear optical chromophores based on the phenyl vinylene thiophene vinylene (FTC) donor-π-acceptor structure have been synthesized and investigated. The donor part of the chromophores was modified with additional donor units, resulting in the enhanced nonlinear optical property with large molecular hyperpolarizability. Hyper-Rayleigh scattering measurement indicated nearly threefold increase of the molecular hyperpolarizability for novel chromophores compared with the benchmark FTC chromophore. Furthermore, measurement of the electro-optic coefficient confirmed that enhancement of microscopic molecular hyperpolarizability of the chromophores can be effectively translated into macroscopic electro-optic property. Measured electro-optic coefficients were nearly twofold larger than that for the benchmark FTC. Thermal analysis indicated that the synthesized chromophores showed the excellent temperature stability with decomposition temperatures up to 280 °C.

ChemInform Abstract: Organometallic Materials for Nonlinear Optics

Almost three decades ago, the field of nonlinear optics evolved with the discovery of lasers. In the beginning, nonlinear optical (NLO) phenomena were investigated in inorganic materials, leading to the development of traditional NLO materials such as lithium niobate, potassium titanyl phosphate, quartz and gallium arsenide. In the 1970s, the importance of organic materials was realized because of the promise of large NLO responses, high laser damage thresholds, fast optical responses, architectural flexibility and ease of fabrication. Following work with organic materials, the scrutiny of organometallics also began recently. In organometallics, the metal-ligand bonding is expected to display large molecular hyperpolarizability because of the transfer of electron density between the metal atom and the conjugated ligand system. In organometallics, the diversity of central metals, oxidation states and ligands fosters in optimization of the charge-transfer interactions. Keeping this in view, second- and third-order NLO properties of organometallics have been reviewed here, highlighting new materials that are emerging. Organometallics may have a wide range of applications in opto-electronics including integrated optics, optical switching, telecommunications, bistability and modulation.

Control of the Orientational Order and Nonlinear Optical Response of the “Push-Pull” Chromophore RuPZn via Specific Incorporation into Densely Packed Monolayer Ensembles of an Amphiphilic Four-Helix Bundle Peptide: Characterization of the Peptide−Chromophore Complexes

"Push-pull" chromophores based on extended pi-electron systems have been designed to exhibit exceptionally large molecular hyperpolarizabilities. We have engineered an amphiphilic four-helix bundle peptide to vectorially incorporate such hyperpolarizable chromophores having a metalloporphyrin moiety, with high specificity into the interior core of the bundle. The amphiphilic exterior of the bundle facilitates the formation of densely packed monolayer ensembles of the vectorially oriented peptide-chromophore complexes at the liquid-gas interface. Chemical specificity designed into the ends of the bundle facilitates the subsequent covalent attachment of these monolayer ensembles onto the surface of an inorganic substrate. In this article, we describe the structural characterization of these monolayer ensembles at each stage of their fabrication for one such peptide-chromophore complex designated as AP0-RuPZn. In the accompanying article, we describe the characterization of their macroscopic nonlinear optical properties.

Synthesis, crystal growth, structural, spectral and optical properties of tri-allylthiourea mercury bromide (ATMB) single crystals

Metal-organic tri-allylthiourea mercury bromide (ATMB) is a new kind of double ligand complex single crystal. Incorporation of metals into NLO systems give a new dimension of study and introduce many new variables. Transfer of unlocalized electrons from the double ligand allylthiourea to the central metal ion (Hg 2+) through the sulphur atom display a large molecular hyperpolarizability. Experimental results show that the solubility of ATMB in aqueous solution is very low and also it is difficult to grow a large size crystal. Attempts were made to grow single crystals of ATMB by solution growth methods. Structural, spectral, optical and surface features of ATMB were studied with different characterization techniques. Trigonal crystal structure of the as-grown single crystals was identified from the powder X-ray diffraction. X-ray rocking curve contains a single sharp peak and indicates that the specimen is free from structural grain boundaries. Vibrational spectral analyses reveal that the metal–ligand coordination occur, only through sulphur and not with nitrogen by shifting the vibration frequencies of υ (N–C–N) to the higher and υ(C=S) to the lower values. ATMB has UV cut-off wavelength at 340 nm and there is no absorption up to 1500 nm which is more desirable for non-linear applications.

Evolution of Linear Absorption and Nonlinear Optical Properties in V-Shaped Ruthenium(II)-Based Chromophores

In this article, we describe a series of complexes with electron-rich cis-{Ru(II)(NH(3))(4)}(2+) centers coordinated to two pyridyl ligands bearing N-methyl/arylpyridinium electron-acceptor groups. These V-shaped dipolar species are new, extended members of a class of chromophores first reported by us (Coe, B. J. et al. J. Am. Chem. Soc. 2005, 127, 4845-4859). They have been isolated as their PF(6)(-) salts and characterized by using various techniques including (1)H NMR and electronic absorption spectroscopies and cyclic voltammetry. Reversible Ru(III/II) waves show that the new complexes are potentially redox-switchable chromophores. Single crystal X-ray structures have been obtained for four complex salts; three of these crystallize noncentrosymmetrically, but with the individual molecular dipoles aligned largely antiparallel. Very large molecular first hyperpolarizabilities beta have been determined by using hyper-Rayleigh scattering (HRS) with an 800 nm laser and also via Stark (electroabsorption) spectroscopic studies on the intense, visible d --> pi* metal-to-ligand charge-transfer (MLCT) and pi --> pi* intraligand charge-transfer (ILCT) bands. The latter measurements afford total nonresonant beta(0) responses as high as ca. 600 x 10(-30) esu. These pseudo-C(2v) chromophores show two substantial components of the beta tensor, beta(zzz) and beta(zyy), although the relative significance of these varies with the physical method applied. According to HRS, beta(zzz) dominates in all cases, whereas the Stark analyses indicate that beta(zyy) is dominant in the shorter chromophores, but beta(zzz) and beta(zyy) are similar for the extended species. In contrast, finite field calculations predict that beta(zyy) is always the major component. Time-dependent density functional theory calculations predict increasing ILCT character for the nominally MLCT transitions and accompanying blue-shifts of the visible absorptions, as the ligand pi-systems are extended. Such unusual behavior has also been observed with related 1D complexes (Coe, B. J. et al. J. Am. Chem. Soc. 2004, 126, 3880-3891).

Toward highly efficient NLO chromophores: Synthesis and properties of heterocycle-based electronically gradient dipolar NLO chromophores

To realize organic nonlinear optical (NLO) chromophores with optimized ground-state polarization and very large molecular optical nonlinearities, a novel series of heterocycle-based electronically gradient dipolar chromophores were designed and synthesized. These chromophores are featured by their same strong electron acceptor (i.e., 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran, TCF) and the same length of π-conjugation, but different electron donors (e.g., dialkylamine and dianisylamine), different (hetero)aromatics with varying electron densities (i.e., pyrrole, thiophene, and benzene) as the auxiliary donor, and electron-poor 1,3-heteroaromatic thiazole with different regiostructures (e.g., either electron-poor C2, “matched”, or electron-rich C5, “un-matched”, is connected to the acceptor) as the auxiliary acceptor, which allows for a systematic fine-tuning of the ground-state polarization. The gradient electronic structures and optical properties of these NLO chromophores were carefully characterized by 1H NMR, CV, UV-vis, and Hyper-Rayleigh scattering experiments. All the NLO chromophores exhibited very large static molecular first hyperpolarizabilities (β0) in the range of 450–960 × 10−30 esu, which showed significant dependence on the gradient electronic structures. Upon using electron-rich heteroaromatic cycle as the auxiliary donor, “matched” thiazole as the auxiliary acceptor, and/or dianisylamine as the electron donor, substantially enhanced β were obtained. Theoretical studies were carried out to understand the structure-property relationships, which showed that multiple states excitations contributed to the β values of this series of NLO chromophores. TGA investigations showed excellent thermal stability for most of the resulting NLO chromophores, with on-set temperatures for thermal decomposition higher than 250 °C. The very large β0 values coupled with the high thermal stability indicates good application potential of this series of NLO chromophores.

Charge‐Transfer State and Large First Hyperpolarizability Constant in a Highly Electronically Coupled Zinc and Gold Porphyrin Dyad

We report the synthesis and the characterizations of a novel dyad composed of a zinc porphyrin (ZnP) linked to a gold porphyrin (AuP) through an ethynyl spacer. The UV/Vis absorption spectrum and the electrochemical properties clearly reveal that this dyad exhibits a strong electronic coupling in the ground state as evidenced by shifted redox potentials and the appearance of an intense charge-transfer band localized at lambda = 739 nm in dichloromethane. A spectroelectrochemical study of the dyad along with the parent homometallic system (i.e., ZnP-ZnP and AuP-AuP) was undertaken to determine the spectra of the reduced and oxidized porphyrin units. Femtosecond transient absorption spectroscopic analysis showed that the photoexcitation of the heterometallic dyad leads to an ultrafast formation of a charge-separated state ((+)ZnP-AuP(*)) that displays a particularly long lifetime (tau = 4 ns in toluene) for such a short separation distance. The molecular orbitals of the dyad were determined by DFT quantum-chemical calculations. This theoretical study confirms that the observed intense band at lambda = 739 nm corresponds to an interporphyrin charge-transfer transition from the HOMO orbital localized on the zinc porphyrin to LUMO orbitals localized on the gold porphyrin. Finally, a Hyper-Rayleigh scattering study shows that the dyad possesses a large first molecular hyperpolarizability coefficient (beta = 2100x10(-30) esu at lambda = 1064 nm), thus highlighting the valuable nonlinear optical properties of this new type of push-pull porphyrin system.

Photoswitching of the third-order nonlinear optical properties of azobenzene-containing phthalocyanines based on reversible host–guest interactions

Two water soluble azobenzene and phthalocyanine dyads with D–π–A alignment were synthesized. It was found that both compounds showed very large molecular cubic hyperpolarizabilities which are at the order of 10−30esu as the result of their unique chemical structure. The azobenzene moieties of these compounds, upon alternating illumination of UV and visible light, could reversibly associate with α-CD to form inclusion complexes through host–guest interaction in aqueous media, resulting in apparent influences to the 3rd NLO properties of these compounds. This influence is especially significant for the phthalocyanine whose central metal atom is copper (II). The molecular cubic hyperpolarizability γ of the inclusion complex for the copper phthalocyanine is 2.1×10−30esu. When the inclusion complex dissociated under the illumination of 365nm light, γ value increased to 4.2×10−30esu, which is a 100% enhancement. Taking account of the large molecular cubic hyperpolarizabilities of these compounds, the present materials are potential as ideal 3rd NLO photoswitching systems.

Synthesis and properties of NLO chromophores with fine-tuned gradient electronic structures

A novel series of heterocycle-based NLO chromophores based on different combinations of auxiliary donor (i.e., benzene, thiophene and pyrrole) and auxiliary acceptor (i.e., thiazole with different regiochemistries) were designed and synthesized. Due to the different electron-rich and poor nature of the auxiliary donors and acceptors, respectively, the resulting NLO chromophores have systematically varied ground-state electronic structures, as evidenced by the 1H NMR, CV and UV-vis investigations. The nonlinear optical properties of the resulting NLO chromophores were studied by UV-vis spectroscopy, Hyper-Rayleigh scattering (HRS), and semi-empirical computations. All the chromophores have very large molecular hyperpolarizabilities (β1000 nm) in the range of 704–1500 × 10−30 esu (or β0, 318–768 × 10−30 esu), which showed a great sensitivity to the gradient electronic structures. Upon increasing the electron density from benzene to thiophene and to pyrrole, substantial increases in β0 were observed; significantly larger β0 values were also observed for NLO chromophores based on “matched” thiazole (C2 is connected to the acceptor) than those based on “un-matched” thiazole (C5 is connected to the acceptor). TGA investigations showed good thermal stability for the resulting NLO chromophores. However, with the increase of electron density of the auxiliary donor, a decrease in thermal and photochemical stability was observed. It is interesting to note that NLO chromophores based on triarylamine as the donor and thiazole as the auxiliary acceptor exhibited not only high thermal stability but also very large β0 values.

Functionalized Picolinium Quinodimethane Chromophores for Electro-Optics: Synthesis, Aggregation Behavior, and Nonlinear Optical Properties

A new series of functionalized and thermally stable zwitterionic picolinium (dicyano)esterquinodimethane (PeQDM) chromophores have been synthesized in one step from 7,8-di(methoxycarbonyl)-7,8-dicyanoquinodimethane (DMCQ) and various picolinium salts in methanol in nearly 50% overall yields. Hyper-Rayleigh scattering (HRS) measurements at 1.07 μm show very large near-resonant molecular first hyperpolarizabilities β up to 1800 × 10−30 esu, despite the fact that, compared to previously studied zwitterionic NLO chromophores, one of the strong CN acceptor groups is substituted by a weaker ester group to allow for further functionalization. The ester functionality can be further utilized for attachment of solubility-imparting groups, cross-linkers, and reactive groups for grafting the chromophore onto a polymer. To optimize the electro-optic (EO) activity in the polymer matrix, the aggregation behavior of the PeQDM chromophores is studied. X-ray crystallographic analysis confirms the charge-separated ground-state of PeQDM and reveals the formation of a face-to-face, antiparallel H-aggregation with a large slip angle (θ = 64.5°) between the chromophores. In a less polar polymer matrix, PeQDM chromophores can form H- and/or J-aggregates and only J-aggregates could contribute to the EO activity if the monomeric chromophores released during the thermally induced J−H transformation could be captured and effectively poled. In a more polar polymer host, chromophores are well dissolved as monomers and effectively poled. A large and stable EO activity (r33 = 110 pm/V) has been achieved with a polyethersulfone film doped with 5 wt % of N-benzyl picolinium (dicyano)esterquinodimethane (PeQDM-Ben).