Stille Coupling Reaction Research Articles

Synthesis and characterization of a pentaselenophene-based donor–acceptor copolymer for use in organic photovoltaic cells

A new conjugated polymer containing pentaselenophene (5Se) electron donor moieties was designed for use in polymer solar cells and synthesized via a Stille coupling reaction. The structure, optical properties, electrochemical properties, hole mobility, photovoltaic properties, and AFM morphology of the homopolymer (P5Se) and the donor–acceptor copolymer (P5SeDTDPP) with a diketopyrrolopyrrole (DPP) acceptor were investigated and are discussed. The polymers showed good solubility, film-forming properties, and thermal stabilities. P5Se exhibited a broad absorption across the visible range, 400–700nm, which is a prerequisite for photovoltaic applications. P5SeDTDPP yielded a broader absorption spectrum, enhanced π–π interactions, and a lower band gap compared to P5Se, due to the enhanced intramolecular charge transfer interactions between the donating moiety (pentaselenophene) and the DPP accepting moiety. Solution-processed field effect transistors fabricated from these polymers displayed p-type organic thin film transistor characteristics. P5Se and P5SeDTDPP exhibited typical p-type organic semiconductor characteristics with hole mobilities of 2.3×10−3 and 1.2×10–2cm2V−1s−1, respectively. Photovoltaic devices were fabricated using polymer:PCBM blends in ITO/PEDOT:PSS/blend/Al structures. The P5SeDTDPP device exhibited an open circuit voltage (VOC) of 0.44V, a short circuit current (JSC) of 10.67mA/cm2, a fill factor (FF) of 0.51, and a power conversion efficiency (PCE) of 2.40% under AM 1.5G (100mW/cm2) conditions.

A Stereoselective Approach to (Z)-1-Silyl-2-aryl-1,3-dienes from 4-(Phenylselanyl)but-1-yne via Palladium-Catalyzed Silylstannylation and Selenoxide Elimination

The palladium-catalyzed silylstannylation of 4-(phenylselanyl)but-1-yne proceeded regio- and stereoselectively, followed by selenoxide elimination via oxidation to give (Z)-1-(trimethylsilyl)-2-(tributylstannyl)buta-1,3-diene in good yield. This conjugated diene underwent the Stille coupling reaction with various aryl iodides in the presence of Pd(PPh3)4 to afford (Z)-2-aryl-1-(trimethylsilyl)buta-1,3-dienes with high stereoselectivity. Reversing the order of selenoxide elimination and Stille coupling reaction in the synthetic procedure also resulted in good yields of (Z)-2-aryl-1-(trimethylsilyl)buta-1,3-dienes.

Synthesis and characterization of naphthalene diimide polymers based on donor-acceptor system for polymer solar cells

Three donor-acceptor (D-A) naphthalene diimide copolymers, poly{thieno(3,2-b)thiophene-diyl-alt-N,N!-bis(2- octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)}(P1), poly{4,8-dioctyloxybenzo(1,2-b;3,4-b!)dithiophene-diyl-alt- N,N!-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)}(P2), and poly{4,8-bis(2-ethylhexyloxy)benzo(1,2- b:4,5-b!)dithiophene-diyl-alt-N,N!-bis(2-octyldodecyl) -naphthalene-1,4,5,8-bis(dicarboximide)}(P3), were synthesized by Stille coupling reaction. All copolymers showed good solubility in common organic solvents with broad absorption region and narrow optical band gap. The electrochemical properties of the polymers can be adjusted by changing the donor seg- ment. P1 showed n-type characteristic while P2 and P3 showed p-type characteristic. All-polymer solar cells using P3HT as the donor and P1 as the acceptor were fabricated and the highest power conversion efficiencies (PCEs) of 0.068% were obtained under the preliminary condition. Moreover, p-type naphthalene diimide copolymers (P2 and P3) based on D-A system were used as donors to fabricate bulk heterojunction polymer solar cells (BHJ, PSCs) for the first time, and the max- imum power conversion efficiencies PCEs were about 0.021 and 0.017%, respectively.

Donor–acceptor conjugated polymers of arylene vinylene with pendent phenanthro[9,10-d]imidazole for high-performance flexible resistor-type memory applications

We report the synthesis and resistive memory device characteristics of new donor–acceptor (D–A) conjugated poly(arylene vinylene) polymers, PVC-PI, PVT-PI, and PVTPA-PI, consisting of carbazole (C), thiophene (T), and triphenylamine (TPA) with pendent phenanthro[9,10-d]imidazole (PI). PVC-PI, PVT-PI, and PVTPA-PI synthesized by Stille coupling reaction have the optical band gaps of 2.86, 1.68, and 2.58 eV, respectively. These polymers possess similar HOMO energy levels (−5.08 to −5.18 eV), but different LUMO energy levels (−2.24, −3.40, and −2.60 eV for PVC-PI, PVT-PI, and PVTPA-PI, respectively). The PVC-PI flexible device with the sandwich configuration of PEN/Al/polymer/Al reveals the volatile static random access memory (SRAM) characteristic while the PVTPA-PI device exhibits the nonvolatile write-once-read-many-times (WORM) switching behavior. The above two devices could operate at low voltages (less than 2.5 V) with high ON/OFF current ratios (over 104) and exhibit excellent durability upon repeated bending tests. However, the PVT-PI device only shows a diode-like electrical behavior. The polymer conformation affects the strength of D–A electrical polarization and charge trapping ability, leading to the variation of the volatility of the memory devices. The present study demonstrates that the prepared vinylene-based donor–acceptor conjugated polymers have excellent memory characteristics with reproducibility and reliability for advanced flexible organic electronics.

An A–D–A small molecule based on the 3,6-dithienylcarbazole electron donor (D) unit and nitrophenyl acrylonitrileelectron acceptor (A) units for solution processed organic solar cells

A new A–D–A small molecule (SM) based on a 3,6-dithienylcarbazole donor unit at the center and nitrophenyl acrylonitrile acceptor units as the terminal ends was synthesized by the Pd catalyzed Stille coupling reaction for application as a donor material in the organic bulk heterojunction solar cells. The SM possesses a low lying HOMO energy level at −5.34 eV and optical band gap of 1.74 eV. The photovoltaic performance of the SM was investigated with PC60BM and PC70BM as acceptors cast from THF with 3% CN additive and without additive. The power conversion efficiency (PCE) of the organic solar cells based on SM:PC60BM cast from THF solvent reached 1.94% with a high Voc of 0.94 V, a Jsc of 6.08 mA cm−2 and FF of 0.34, where as the PCE of SM:PC70BM cast from THF solvent was 2.65% with a Voc of 0.96 V, a Jsc of 7.26 mA cm−2 and FF of 0.38%, under the illumination intensity of 100 mW cm−2. The higher PCE of the organic solar cells based on PC70BM as an electron acceptor has been attributed to its strong absorption in the visible region than PC60BM. The PCE of the organic solar cells has been further improved to 3.76% and 4.96% for SM:PC60BM and SM:PC70BM, respectively, cast with CN–THF solvent.

Synthesis, photophysics and electrochemistry of novel, nitrogen-containing heterocyclic derivatives

A series of new π-conjugated donor (thienyl – T) and acceptor (A) oligomers were prepared by Stille coupling reaction. The T–A oligomers consisting of thiophene/bithiophene as donors and 1,2,4-triazine as an acceptor were prepared to investigate their photophysical and electrochemical properties. These compounds were spectroscopically confirmed to be highly conjugated. These UV-vis data show that the number and position of the thiophene considerably affect the width of the HOMO–LUMO gap and the rigidity of the conjugated system. Compounds A2TA, A3TA, A4TA show photoluminescence in a range 466–543 nm.

Solution-processable blue-to-transmissive electrochromic benzotriazole-containing conjugated polymers

A series of donor–acceptor type electrochromic (EC) conjugated polymers P1–P4, poly(4,7-bis(3′,4′-ethylenedioxythiophen-2′-yl)-2-alkylbenzotriazole-5′,5′-diyl-alt-(3,4-dialkoxy-thiophen-2,5-diyl), was synthesized via a Stille coupling reaction. The polymers were characterized by gel permeation chromatography (GPC), nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The electrochemical, spectroelectrochemical and EC properties of the polymers were studied. The polymers displayed improved solubility in common organic solvents. Upon oxidation, the polymers switched from a saturated blue to a transmissive light blue state. In particular, P4 exhibited exceptional optical contrasts of 46% and 72% in the visible and near-infrared regions, respectively. Furthermore, the effects of the side chains on the EC properties were examined and the results revealed that polymers with a long alkyl chain in the benzotriazole moiety had faster switching speed both in the visible and near infrared regions in the polymer film state. The absorption–transmission ECDs were fabricated, revealing that under ambient conditions and without any encapsulation of ECDs, the polymers exhibited good optical contrasts and coloration efficiencies with improved stability.

Synthesis, crystal structure, and polymerization of butterfly-shaped thieno[3,2-b]thiophene oligomers

A series of new butterfly-shaped thieno[3,2-b]thiophene oligomers with phenyl and thiophene units were synthesized through Suzuki coupling and Stille coupling reactions. The optical and thermal properties of these materials can be tuned by varying both substituents and the conjugation length. The crystal structures have been determined and showed a syn- or anticlinal conformation in the crystal of molecule 4. The electronic properties of the monomers and their electropolymerization ability are discussed and rationalized as a function of their molecular structure. Moreover, stable cross-linked conjugated polymers were formed by electropolymerization.

Anthradithiophene-benzothiadiazole-based small molecule donors for organic solar cells

A new A–D–A small molecule involving anthradithiophene as a donor and benzothiadiazole as an acceptor unit has been synthesized by Stille coupling reaction. Its thermal, optical and electronic properties, hole mobility and photovoltaic properties have been fully characterized. The resulting material shows a broad absorption range (300–750 nm), a low band gap (1.59 eV) and a moderate hole mobility (8.81 × 10−4 cm2 V−1 s−1). We used the new small molecule blended with PC71BM as the active layer to fabricate solution-processed organic solar cells (OSCs), and employed a variety of post-treatment methods to optimize the device performance. With the help of polar solvent exposure, the highest power conversion efficiency (PCE) of 0.55% was obtained. These results would supply useful information to understand the relationship between molecular structure and photovoltaic properties of anthradithiophene/benzothiadiazole-based OSCs.

A benzo[1,2-b:4,5-b′]difuran- and thieno-[3,4-b]thiophene-based low bandgap copolymer for photovoltaic applications

A new low bandgap conjugated polymer—PBDFTT-C was synthesized from thieno-[3,4-b]thiophene and benzo[1,2-b:4,5-b′]difuran units by Stille coupling reactions. The structure was verified by 1H NMR and elemental analysis, the molecular weight was determined by gel permeation chromatography (GPC) and the thermal properties were investigated by thermogravimetric analysis (TGA). PBDFTT-C showed a low HOMO energy level of −5.27 eV. The polymer film displayed broad absorption in the wavelength region from 300 nm to 840 nm with a low bandgap of 1.48 eV. The field effect hole mobility of PBDFTT-C reached 5.4 × 10−3 cm2 V−1 s−1. By using 1,8-diiodooctane (DIO) as the solvent additive, photovoltaic cells with the structure of ITO/PEDOT:PSS/PBDFTT-C:PC71BM (1 : 1.5, w/w)/Ca/Al demonstrated a power conversion efficiency of 4.4% with a short circuit current of 10.45 mA cm−2, open circuit voltage of 0.66 V and a fill factor of 0.64, under the illumination of AM 1.5G, 100 mW cm−2.

Photovoltaic properties and annealing effects of a low bandgap copolymer containing dithienothiophene and benzothiadiazole units

A conjugated alternating copolymer as the donor material of the active layer in polymer solar cells has been designed and synthesized via Stille coupling reaction. The alternating structure consisted of 3,5-didecanyldithieno(3,2- b:2!,3!-d)thiophene (DDTT) donor unit and 5,6-bis(tetradecyloxy)benzo-2,1,3-thiadiazole (BT) acceptor unit. Since both units have been attached pendant chains, the polymer was soluble in common organic solvents. UV-vis spectrum exhibited a broad absorption band in the range of 270-780 nm and a low bandgap of 1.83 eV. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the polymer were estimated to be -5.10 and -3.27 eV, respectively. Based on the ITO/PEDOT:PSS/PDDTTBT:PCBM/Al device structure, the power conversion effi- ciency (PCE) under the illumination of AM 1.5 (100 mW/cm 2 ) was 0.127%. The effects of annealing temperature (50- 150°C) for 30 min on the device performance were studied. It was found that PCE of 0.292% could be acquired under the annealing condition at 50°C for 30 min. The improved device efficiency under the optimal condition was confirmed by the higher light harvest in UV-vis spectra, the enhanced quenching of photoluminescence (PL) emission, and the improved nanoscale morphology by atomic force microscopy (AFM) examination.

A Promising Ketone Containing Alternating Copolymer for Organic Photovoltaics

ABSTRACTAn alternating copolymer containing dithienylcyclopentadienone, thiophene and benzothiadiazole was synthesized by palladium (0) catalyzed Stille coupling reaction. Structural characterization of the synthesized alternating copolymer was carried out by NMR and FTIR spectroscopy. This solution processable copolymer shows an excellent thermal stability and has a broad absorption range from 300-800 nm. High LUMO energy level and low band gap of the synthesized copolymers suggest that, this copolymer will be a better donor material for application in organic photovoltaics. Particle size analysis and molecular weight determination of the synthesized copolymer through dynamic light scattering experiment indicates that, high molecular weight copolymer was obtained by this polymerization route. Photovoltaic devices were fabricated from the blend of copolymer and phenyl-C61- butyric acid methyl ester as the active material. Fabricated photovoltaic device results show that this alternating copolymer is a promising candidate for use in organic photovoltaics.

Stability, surface features, and atom leaching of palladium nanoparticles: toward prediction of catalytic functionality

Surfactant-stabilized metal nanoparticles have shown promise as catalysts although specific surface features and their influence on catalytic performance have not been well understood. We quantify the thermodynamic stability, the facet composition of the surface, and distinct atom types that affect rates of atom leaching for a series of twenty near-spherical Pd nanoparticles of 1.8 to 3.1 nm size using computational models. Cohesive energies indicate higher stability of certain particles that feature an approximate 60/20/20 ratio of {111}, {100}, and {110} facets while less stable particles exhibit widely variable facet composition. Unique patterns of atom types on the surface cause apparent differences in binding energies and changes in reactivity. Estimates of the relative rate of atom leaching as a function of particle size were obtained by the summation of Boltzmann-weighted binding energies over all surface atoms. Computed leaching rates are in good qualitative correlation with the measured catalytic activity of peptide-stabilized Pd nanoparticles of the same shape and size in Stille coupling reactions. The agreement supports rate-controlling contributions by atom leaching in the presence of reactive substrates. The computational approach provides a pathway to estimate the catalytic activity of metal nanostructures of engineered shape and size, and possible further refinements are described.

Taking the place of perylene diimide: perylene tetracarboxylic tetraester as a building block for polymeric acceptors to achieve higher open circuit voltage in all-polymer bulk heterojunction solar cells

As strong electron acceptors, perylene diimides (PDI) have been widely utilized to prepare polymeric acceptors with an alternating donor–acceptor (D–A) structure for all-polymer solar cell applications, and which are used to provide low open circuit voltage (Voc). Cyclic voltammetry measurements reveal that both the HOMO and LUMO levels of a structurally related analogue to PDI, perylene tetracarboxylic tetraester (PTTE), are 0.3 eV higher than those of the corresponding PDI. It was envisioned that replacing PDI by the weaker electron acceptor of PTTE in making polymeric acceptors with D–A structure could help to raise the LUMO level of the resultant polymers, which would lead to a higher Voc when these PTTE based polymers are used as acceptors in all-polymer solar cell devices. In this work, a new conjugated alternating copolymer, poly([perylene tetracarboxylic tetra(2-hexyldecyl)ester-1,7-diyl]-alt-5,5′′-(2,2′:5′,2′′-terthiophene)) (PPTTE-TerT), was synthesized via Stille coupling reaction and characterized as an electron acceptor. The copolymer shows good solubility in common aliphatic organic solvents and good thermal stability. Differential scanning calorimetry (DSC) and grazing incident X-ray diffraction (GIXRD) measurements indicate that the copolymer at solid state is amorphous. PPTTE-TerT has a relatively broad absorption in the visible region from 400–650 nm with an optical band gap of 1.91 eV. The energy levels of HOMO and LUMO derived from the onset of the first oxidation and reduction potential of the cyclic voltammograms are at −5.6 and −3.54 eV, respectively. All-polymer solar cells of regioregular poly(3-hexylthiophene) (RR-P3HT) as the donor and PPTTE-TerT as the acceptor at an optimized donor–acceptor weight ratio of 1:0.7 achieved the best power conversion efficiency of 0.76%. The Voc is 0.83 V, the short-circuit current (Jsc) is 2.38 mA cm−2 and the fill factor (FF) is 0.34 under 1 sun (100 mW cm−2) AM1.5G solar illumination. The Voc value is about 0.3 V higher than that of the all-polymer solar cell based on blending RR-P3HT with the acceptor copolymer comprised of alternating PDI-terthiophene units, which is consistent with the fact that the LUMO level of PTTE is 0.3 eV higher than that of PDI. These results indicate that PTTE is a promising electron-accepting unit to construct polymeric acceptors to be used in all-polymer BHJ solar cells.

Synthesis and simultaneously enhanced photovoltaic property of poly[4,4,9,9-tetra(4-octyloxyphenyl)-2,7-indaceno[1,2-b:5,6-b′]dithiophene-alt-2,5-thieno[3,2-b]thiophene

An alternating conjugated polymer derived from 4,4,9,9-tetra(4-octyloxyphenyl)indaceno[1,2-b:5,6-b′]dithiophene and thieno[3,2-b]thiophene was synthesized by Stille coupling reaction. The copolymer shows extensive absorption from 360 nm to 590 nm with optical band gap of 2.12 eV. The highest occupied molecular orbit (HOMO) and the lowest unoccupied molecular orbit (LUMO) energy levels of the copolymer, determined by cyclic voltammetry (CV), are about −5.29 eV and −3.01 eV, respectively. A field-effect hole mobility of 8.1 × 10−4 cm2/(V s) and an on/off ratio of 2.0 × 103 are obtained in the field-effect transistors based on the copolymer. The Jsc, Voc and FF of the polymer photovoltaic cells (PVCs) based on the copolymer were enhanced simultaneously via the inserting of alcohol soluble conjugated polymer interlayer between active layer and metal cathode, and the maximal power conversion efficiency of 4.19% was achieved in the modified devices under an AM 1.5 simulator (100 mWcm−2).

Synthesis and photovoltaic properties of dithienosilole-based copolymers

Two novel narrow bandgap random dithienosilole copolymers based on 3,3′-di-n-octylsilylene-2,2′-bithiophene (DTS), ethylene (E), 4,7-bis(-4-hexyl-2-thienyl)-2,1,3-benzothiadiazole (DTBT), or 6,7-diphenyl-4,9-bis(4,4′-dihexyl-2,2′-bithiophen-5-yl)-[1,2,5]-thiadiazolo[3,4-g]quinoxaline (PhDTTQ) have been synthesized by means of Pd-catalyzed Stille coupling reactions. The electrochemical, optical and photovoltaic properties of the copolymers were studied. The absorption spectrum of the copolymer PDTSE-DTBTE in thin film has one absorption peak at 668 nm, and the absorption spectrum of the copolymer PDTSE-PhDTTQ displays two absorption peaks at about 594 and 841 nm. The bulk heterojunction solar cells were fabricated with the as-synthesized copolymers as the donors and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) as the acceptor in a 1:1 weight ratio in the device configuration ITO/PEODT/copolymer:PC61BM (1:1)/Al. The power conversion efficiency of the device based on copolymer PDTSE-DTBTE is 0.72 % with open-circuit voltage (V oc) 0.5 V under simulated AM 1.5 G solar irradiation (100 mW/cm2).

Synthesis of Thiophene-Based π-Conjugated Polymers Containing Oxadiazole or Thiadiazole Moieties and Their Application to Organic Photovoltaics

We report the synthesis, properties, and photovoltaic applications of new π-conjugated polymers having thiophene, 3,4-dihexylthiophene, and 1,3,4-oxadiazole (OXD) or 1,3,4-thiadiazole (TD) units in the main chain, denoted as P1 and P2. They were synthesized by the Stille coupling reaction of 2,5-bis(trimethylstannyl)thiophene and the corresponding monomers of 2,5-bis(5′-bromo-3′,4′-dihexylthien-2′-yl)-1,3,4-oxadiazole or 2,5-bis(5′-bromo-3′,4′-dihexylthien-2′-yl)-1,3,4-thiadiazole, respectively. The experimental results indicated that the introduction of an electron-accepting moiety of OXD or TD lowered the highest occupied molecular orbital (HOMO) energy levels, resulting in the higher the open-circuit voltage (Voc) values of polymer solar cells (PSCs). Indeed, the PSCs of P1 and P2 showed high Voc values in the range 0.80–0.90 V. The highest field-effect transistor (FET) mobilities of P1 and P2 with the OXD and TD moieties, respectively, were 1.41 × 10–3 and 8.81 × 10–2 cm2 V–1 s–1. The higher mobility ...

Synthetic Studies towards NG-121: Diastereoselective Synthesis of NG-121 Methyl Ether

Starting from unsymmetrically O-protected methyl 4-bromo-3,5-dihydroxybenzoate, a facile synthesis of the methyl ether of bioactive natural product NG-121 was accomplished in very good overall yield. The key steps were: Stille coupling reaction of the farnesyl unit with the electron-rich phenolic segment; hydroxy-directed selective epoxidation of the farnesyl chain along with concomitant phenol-driven intramolecular regio- and diastereoselective ring closure to the corresponding hydroxybenzopyran; and regioselective formylation followed by in situ reductive lactonization.

Low‐bandgap quinoxaline‐based D–A‐type copolymers: Synthesis, characterization, and photovoltaic properties

AbstractThree classes of quinoxaline (Qx)‐based donor–acceptor (D–A)‐type copolymers, poly[thiophene‐2,5‐diyl‐alt‐2,3‐bis(4‐(octyloxy)phenyl‐quinoxaline‐5,8‐diyl] P(T‐Qx), poly{4,8‐bis(2‐ethylhexyloxy)benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl‐alt‐2,3‐bis(4‐(octyloxy)phenyl‐quinoxaline‐5,8‐diy} P(BDT‐Qx), and poly{4,8‐bis(2‐ethylhexyloxy)benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl‐alt‐(5′,8′‐di‐2‐thienyl‐2,3‐bis(4‐octyloxyl)phenyl)‐quinoxaline‐5,5‐diyl} P(BDT‐DTQx), were synthesized via a Stille coupling reaction. The Qx unit was functionalized at the 2‐ and 3‐positions with 4‐(octyloxy)phenyl to provide good solubility and to reduce the steric hindrance. The absorption spectra of the Qx‐containing copolymers could be tuned by incorporating three different electron‐donating moieties. Among these, P(T‐Qx) acted as an electron donor and yielded a high‐performance solar cell by assuming a rigid planar structure, confirmed by differential scanning calorimetry, UV–vis spectrophotometer, and density functional theory study. In contrast, the P(BDT‐Qx)‐based solar cell displayed a lower power conversion efficiency (PCE) with a large torsional angle (34.7°) between the BDT and Qx units. The BDT unit in the P(BDT‐DTQx) backbone acted as a linker and interfered with the formation of charge complexes or quinoidal electronic conformations in a polymer chain. The PCEs of the polymer solar cells based on these copolymers, in combination with [6,6]‐phenyl C70 butyric acid methyl ester (PC71BM), were 3.3% [P(T‐Qx)], 1.9% [P(BDT‐Qx)], and 2.3% [P(BDT‐DTQx)], respectively, under AM 1.5G illumination (100 mW cm−2). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Synthesis and Characterization of New Thieno[3,2-b]thiophene Derivatives

Three derivatives of thieno[3,2-b]thiophene end-capped with phenyl units have been synthesized and characterized by MALDI TOF mass spectroscopy, elemental analysis, UV-vis absorption spectroscopy and thermogravimetric analysis (TGA). All compounds were prepared using Pd-catalyzed Stille or Suzuki coupling reactions. Optical measurements and thermal analysis revealed that these compounds are promising candidates for p-type organic semiconductor applications.