Photoisomerization Behavior Research Articles

Construction of photoresponsive azobenzene-decorated cationic surfactant-based self-assembled vesicles and controlled drug release

Surfactant aggregates possess a unique feature of space partitioning, and hence are widely used as drug carriers. A comprehensive understanding of the regulation of surfactant aggregation behavior can achieve the controlled release of drugs. In this work, the surface activity and photoisomerization behavior of the synthetically prepared azobenzene-functionalized cationic surfactant (AzoNC8) were thoroughly studied by analyzing the surface tension and UV-Vis absorption data, respectively. Furthermore, the self-assembling tendency of AzoNC8 with β-cyclodextrin (β-CD) was also monitored by proton nucleic magnetic resonance (1H NMR) and scanning electron microscopy (SEM). The AzoNC8 initially formed a 1:1 inclusion complex with β-CD and subsequently 2AzoNC8 @ 2β-CD self assembly unit was formed. At 10 mM concentration, the AzoNC8/β-CD self-assembled system was found to develop a vesicular structure. The photo-responsive property of AzoNC8/β-CD was further investigated using UV-Vis, 1H NMR, and transmission electron microscopy (TEM). The self-assembled system was found to exhibit a fast photo-responsive behavior under UV light and a reversible photo-response under visible light. Interestingly, the photo-induced cis-trans isomerization altered the driving force associated with the self-assembly of AzoNC8/β-CD, thereby modulating the self-assembled morphologies. In addition, an investigation with the antitumor drug of doxorubicin hydrochloride (DOX) at different pH values revealed that the self-assembly-based vesicles exhibited a quick photo-responsive drug release and a weak acid environment could improve the rate and amount of the release. Therefore, the AzoNC8/β-CD self-assembled system might be used for the controlled release of drugs and could be a promising drug carrier.

Azobenzene-containing side-chain ionic metathesis polymers: Facile synthesis, self-assembly and photoresponsive behavior

A series of well-defined azobenzene-functionalized ionomers were produced via ring-opening metathesis polymerization of norbornene-dicarboximide tethered to an ionic group further connected with an azobenzene unit in ionic liquid. The corresponding azobenzene-containing non-ionic polymers were also synthesized by the similar method. All the polymerizations were confirmed to be the characteristic of living based on the linear relationship between molecular weight and feed ratio. As expected, the distinct photoresponsive properties from azobenzene units in ionomers were observed under alternating irradiation of UV and visible light, which cannot be achieved by traditional azobenzene-containing non-ionic polymers. The ability and efficiency of trans−cis photoisomerization was depressed to some extent due to the presence of ionic groups nearby azobenzene units. Moreover, the sizes and morphologies of these ionomers can be modulated through changing the number of the methylene spacer to generate regular and uniform spherical nanostructures, ultimately leading to the unique photoisomerization behaviors. All these interesting results will not only provide a facile and efficient method for constructing photosensitive ionic metathesis polymers, but also expand the optical properties and application prospect of azobenzene-containing polymers.

Outside Back Cover: Volume 2 Issue 3

Outside back cover image: Photo-responsive materials are a category of smart materials to achieve both spatially and temporally tunable photophysical properties, thus attracting extensive attention for the applications toward multifunctional optoelectronic devices. In this article, the authors realize the optical and electrical modulation within organic one-dimensional photochromic arrays. Moreover, the ultraviolet photodetectors based on these photochromic arrays exhibit tunable photoresponsivity performance through adjusting their controllable photoisomerization behaviors. The authors believe this work about optoelectronic properties within onecomponent photochromic system will broaden the integration of future multifunctional optoelectronic devices. (DOI: https://doi.org/10.1002/smm2.1056)

Low-cost photo-switches based on stilbene-appended Zn(II)-terpyridine complexes.

We report herein the synthesis, characterization, photophysics, and photo-isomerization behaviors of three Zn(II)-terpyridine complexes of the type [Zn(tpy-pvp-X)2]2+ (X = H, Me, and NO2) covalently tethered with stilbene moiety. The complexes exhibit absorption bands stretching up to the edge of the visible domain due to ligand → ligand charge transfer (LLCT) transitions and strong emission at room temperature in the visible due to radiative deactivation of 3LLCT state having lifetime within 1.0-3.0ns. The stilbene motifs in the complexes undergo trans to cis isomerization upon irradiating with UV and visible light accompanied by significant alteration of their absorption, emission, and 1H NMR spectral profiles. Apart from the variation of electron donating and electron withdrawing substituent (X), the isomerization studies were also carried out in three different solvents (DCM, MeCN, and DMSO) to further tune their kinetic and thermodynamic parameters. The rate, rate constant and quantum yield of isomerization were estimated in all the solvents. The reverse process (cis to trans) also occurs very slowly on keeping but could be accelerated upon heating. Trans to cis photoisomerization leads to quenching of emission in case of 1 and 2, whereas backward thermal cis to trans conversion leads to restoration of emission. By contrast, for the nitro-derivative (3) forward process induces emission enhancement, while backward process gives rise to emission quenching. In essence, "on-off" and "off-on" emission switching is feasible for 1 and 2, whereas "off-on" and "on-off" emission switching occurs in case of 3. Emission spectral responses upon successive action of photonic and thermal input lead to the fabrication of INHIBIT and IMPLICATION logic gates. DFT and TD-DFT computational investigations were also undertaken to visualize their electronic structures, correct assignment of the spectral bands, and mode of isomerization process.

Optical and electrical modulation in ultraviolet photodetectors based on organic one‐dimensional photochromic arrays

AbstractOrganic photochromic materials have drawn considerable attention for their potential applications in large‐scale and low‐cost optoelectronics owing to unique tunable physicochemical properties. For organic photodetectors, photochromic materials have realized optical and electrical engineering of semiconductor layers, which incorporate not only tunable performance, but also functionalities to optoelectronic devices. However, the essential challenge is to assemble large‐area photochromic micro‐ and nanostructure arrays with controllable geometry and precise alignment, which restricts the integration of multifunctional optoelectronic devices. Herein, we fabricate organic photochromic one‐dimensional (1D) arrays via a feasible solution process through the confined crystallization of organic molecules. By modulating and controlling the photoisomerization behaviors, these 1D photochromic arrays possess broad spectral tunability, which ensure tunable photoresponse. Furthermore, we investigate the crystallographic transition and electronic performance variation of these 1D photochromic arrays. By adjusting the dwell time of ultraviolet (UV) irradiation, the UV photochromic photodetectors realize tunable and repeatable responsivity from 85.6 to 0.709 mA/W. Our work provides new possibilities for optical and electrical engineering of photochromic microwires towards the integration of multifunctional optoelectronic devices.

Solid-state photoswitching in arylazopyrazole-embedded polydimethylsiloxane composite thin films

Arylazopyrazoles (AAPs) show significant potential as a new family of molecular photoswitches owing to their efficient reversible trans -to- cis photoisomerization behavior and the high thermal stability of their metastable cis -isomer. In this study, AAPs have been used for the fabrication of solid-state photoswitchable polydimethylsiloxane (PDMS) based composite thin films. The thin films were prepared by using PDMS as a polymer matrix and different concentrations of AAPs as chromophores at 150 ​°C via spin-coating. The photoswitching behavior of the AAPPDMS composite films and the pristine AAP samples induced by irradiation with specific wavelength of light were investigated. We found that the as prepared AAPPDMS composite films showed rapid and near-quantitative (>98%) reversible trans -to- cis isomerization upon alternating irradiation with UV (λ ​= ​365 ​nm) and green (λ ​= ​525 ​nm) light which is comparable to the isomerization behavior of the pristine AAP chromophores in solution. This indicates that the excellent photoswitching property of the AAPs is preserved in the solid-state of the AAP-PDMS composite films. The results also show that the optical properties of the AAP-PDMS composite films can be tuned by using different ratios of the AAP chromophores and exposure to UV-light irradiation. Additionally, the thin films were tested for their photo-actuation behavior by UV–vis spectroscopy. Irradiation of the thin film with alternating 365 ​nm UV and 525 ​nm green light lead to a slight reversible bending behavior. This is presumably caused by the light-induced conformational change of the AAP moiety embedded within the PDMS matrix and the soft nature of the PDMS. This methodology provides a new approach for exploring the fabrication of polymers with enhanced mechanical behavior and solidstate photoswitching properties. Arylazopyrazoles (AAPs) show significant potential as a new family of molecular photoswitches owing to their efficient reversible trans -tocis photoisomerization behavior and the high thermal stability of their metastable cis - isomer. In this study, AAPs have been used for the fabrication of solid-state photoswitchable polydimethylsiloxane (PDMS) based composite thin films. The thin films were prepared by using PDMS as a polymer matrix and different concentrations of AAPs as chromophores at 150 ​°C via spin-coating. The photoswitching behavior of the AAP-PDMS composite films and the pristine AAP samples induced by irradiation with specific wavelength of light were investigated. We found that the as prepared AAP-PDMS composite films showed rapid and near-quantitative (>98%) reversible trans -to- cis isomerization upon alternating irradiation with UV (λ ​= ​365 ​nm) and green (λ= 525 ​nm) light which is comparable to the isomerization behavior of the pristine AAP chromophores in solution. This indicates that the excellent photoswitching property of the AAPs is preserved in the solid-state of the AAP-PDMS composite films. The results also show that the optical properties of the AAP-PDMS composite films can be tuned by using different ratios of the AAP chromophores and exposure to UV-light irradiation. Additionally, the thin films were tested for their photo-actuation behavior by UV–vis spectroscopy. Irradiation of the thin film with alternating 365 ​nm UV and 525 ​nm green light lead to a slight reversible bending behavior. This is presumably caused by the light-induced conformational change of the AAP moiety embedded within the PDMS matrix and the soft nature of the PDMS. This methodology provides a new approach for exploring the fabrication of polymers with enhanced mechanical behavior and solid-state photoswitching properties.

Emission Switching in the Near-Infrared by Reversible Trans-Cis Photoisomerization of Styrylbenzene-Conjugated Osmium Terpyridine Complexes.

A new array of homoleptic osmium(II) complexes based on styrylbenzene-conjugated terpyridine ligands (tpy-pvp-X) were synthesized and their photophysical, electrochemical, and photoisomerization behaviors thoroughly investigated in this work. Both electron-donating and -withdrawing substituents were incorporated onto a tpy-pvp-X (X = H, Me, Cl, NO2, and Ph) moiety to tune the optical properties and also the rate of photoisomerization behaviors in the complexes. All complexes display strong spin-allowed singlet metal-to-ligand charge-transfer bands in the visible (495-506 nm) and weak singlet ground state to triplet metal-to-ligand charge-transfer (3MLCT) broad bands within the 600-700 nm range. The complexes also exhibit strong phosphorescence emission from their 3MLCT state in the near-infrared domain (737-752 nm) at room temperature with excited-state lifetimes spanning between 107 and 165 ns. Two styrylbenzene units promote reversible trans-trans to trans-cis/cis-cis isomerization induced by light. The rate constants and quantum yields of photoisomerization were found to vary linearly with the Hammett σp parameters of the substituents. The rate and quantum yields were also found to decrease with increasing polarity of the solvents. Considerable modulation of the optical behavior along with luminescence switching in the complexes has been achieved upon photoisomerization. Moreover, the optical outputs as a function of two photonic stimuli inputs were used to demonstrate the binary function of a two-input IMPLICATION logic gate. In conjunction with the experimental study, computational investigations were also carried out in all three conformations of the complexes (trans-trans, trans-cis, and cis-cis) to have a perception of their electronic structures and for correct assignment of their absorption and emission spectral bands.

Synthesis, characterization, and photoinduced deformation properties of a series of azobenzene-containing poly(arylene ether)s

The photoinduced deformation properties in azobenzene-containing polymers can convert light energy into mechanical energy. At present, there are few types of photoinduced deformable polymers based on azobenzene-containing high performance polymers, and new types of high performance azobenzene-containing polymers need to be developed. Here, a series of azobenzene-containing poly (arylene ether)s with various azobenzene contents were synthesized. These azobenzene-containing polymers showed high glass transition temperatures and high thermal stabilities. The photoisomerization behavior and the photoinduced deformation behavior of these azobenzene-containing polymers were studied upon exposure to a 442 nm linearly polarized laser and a 532 nm linearly polarized laser, respectively. Both of the photodeformation rate and the maximum photoinduced bending angles of the polymers increased with increasing azobenzene content. To our knowledge, it is the first report on photoinduced deformation properties of azobenzene-containing poly (arylene ether)s. In addition, the photoinduced bending rate and maximum photoinduced bending angle of the cantilever under 442 nm laser excitation were higher and larger than that under 532 nm laser excitation, respectively.

Photoresponsive molecular tweezer: Control-release of anions and fluorescence switch

Photoresponsive control-release supramolecular systems have aroused considerable interest for the application in drug delivery, ion transport and so on. Here, we fabricated a stiff-stilbenes-based bis-urea that resembles a molecular tweezer, exhibiting reversible photoisomerization behaviors between (Z)-form and (E)-form. Significantly, photo-controlled selective recognition and release of CH3CO2− and H2PO4− were achieved by the molecular tweezer upon irradiation with distinct light. Furthermore, the stiff-stilbenes-based bis-urea also hold a functionalization as a novel photoinduced fluorescence switch. These finds have enormous potential for the application in optically controlled drug delivery, the regulation of anion transport across the cell membrane and advanced optical materials.

Novel amphiphilic ABC 3-miktoarm star azo-copolymer with polypeptide chain: Synthesis, self-assembly and photo-responsive behavior

Well-defined amphiphilic ABC 3-miktoarm star terpolymer containing hydrophilic methoxy poly(ethylene glycol) (MPEG), hydrophobic poly[6-(4-methoxy-azobenzene-4′-oxy) hexyl methacrylate] (PAzoMA) and poly(γ-benzyl-L-glutamic acid) (PBLG) was synthesized by a combination of copper-mediated atom transfer radical polymerization (ATRP) and ring opening polymerization (ROP). MPEG was modified to bear two different functional groups, which were further modified to the initiator of ATRP and ROP for the preparation of the amphiphilic ABC-type 3-miktoarm star terpolymers (MPEG) (PAzoMA) (PBLG). The spindle-like micelles were formed from the amphiphilic 3-miktoarm star terpolymer through a solution self-assembly due to the rigid ɑ-helical conformation of PBLG block and the π-π interaction between PBLG block with PAzoMA block in the star terpolymer. The investigation of the photo-isomerization behavior of (MPEG) (PAzoMA) (PBLG) in solution and in micellar solution showed that trans–cis isomerization in solution was quicker than that in micellar solution, and H- or J-aggregates of the azobenzene groups in the aggregates did not be observed. On the basis of the experimental results, the formation mechanisms of the spindle-like micelles were suggested and the obtained results may expand the self-assembly research field.

Controlled synthesis of azobenzene-containing block copolymers both in the main- and side-chain from SET-LRP polymers via ADMET polymerization

Novel ABA triblock copolymer contained azobenzene (azo) chromophores both in the main- and side-chain was designed and synthesized via combination of single electron transfer-living radical polymerization (SET-LRP) and acyclic diene metathesis (ADMET) polymerization. The α-bromoester end group of side-chain azo-polymer prepared in SET-LRP system using acrylate bearing azo group as monomer was reacted with potassium acrylate to yield azo-polymer with the chain end of α-acrylate, which acted as a monofunctional macromolecular chain stopper for subsequent ADMET polymerization of azo-functionalized α,ω-diene monomer to finally controllable synthesize ABA triblock azo-copolymer. The diluted solutions of main-chain ADMET azo-homopolymer, side-chain SET-LRP azo-homopolymer, and main-side chains azo-copolymer exhibited different photoisomerization behaviors (maximum absorption and rate of photoisomerization) under the irradiation of UV and visible light. All these interesting results could provide a guide for the design of photosensitive materials.

Experimental and theoretical exploration of photophysics and trans-cis photoisomerization of styrylbenzene conjugated terpyridine complexes of Ru(II): Strong effect of deprotonation from second coordination sphere

We report herein synthesis, characterization, photophysics, and photo-isomerization behaviors of a new class of heteroleptic Ru(II) complexes incorporating styrylbenzene conjugated terpyridine and 2,6–bis(benzimidazole–2–yl)pyridine ligands. All the complexes display moderately strong luminescence at room temperature with appreciably long lifetime varying in the range between 7.2 and 62.2 ns, depending upon the electronic nature of substituent as well as the solvent. The styrylbenzene moiety induces trans to cis isomerization resulting in remarkable changes in absorption and both steady state and time-resolved luminescence spectral characteristics upon irradiating with UV light. Reversal of cis to trans isomerization were also achieved on interacting with visible light as well as UV light of specific wavelength. Removal of two benzimidazole NH protons from the secondary coordination sphere of the complexes were made possible upon treatment with strong base accompanying with substantial modulation of their absorption and emission spectral properties. Interestingly, rate constant as well as quantum yield of photoisomerization dramatically increases upon deprotonation of the imidazole NH protons. Computational studies employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were also executed for understanding the electronic charge distribution within the complex backbone and appropriate assignment of the observed spectral bands. In addition, observed spectral trend upon NH deprotonation as well as deprotonation-induced photoisomerization processes were also compared with the calculated results.

Azobenzene-functionalized graphene nanoribbons: bottom-up synthesis, photoisomerization behaviour and self-assembled structures

We show the strategy of introducing azobenzene groups into graphene nanoribbons (GNRs), which not only endows GNRs with fast photo-responsiveness but also induces the self-assembly of the GNRs into ultra-long nanowires.

Heat trapping in a nano-layered microenvironment: estimation of temperature by thermal sensing molecules.

We have previously found reversible photo-induced expansion and contraction of organic/inorganic clay hybrids, and even sliding of niobate nano-sheets at the macroscopic level of organic/inorganic niobate hybrids, induced by the molecular photo-isomerization of the polyfluoroalkylated azobenzene derivative (C3F-Azo-C6H) intercalated within the interlayer, which is viewed as an artificial muscle model unit. Based on systematic investigations of the steady state photo-isomerization and transient behavior of the reaction, we comprehended that the phenomena is caused by trapping of excess energy liberated during the isomerization, as well as the relaxation processes upon excitation of azobenzene chromophores in the interlayers of the hybrid. In this paper, quantitative estimation of transient 'heat' trapped in various microenvironments has been studied by each co-intercalation of temperature sensing dye molecules - rhodamine B (RhB) or tris(bipyridine)ruthenium(ii) chloride (Rubpy) with C3F-Azo-C6H within clay (SSA) nano-layers. The amount of dye molecules co-intercalated was kept to trace amounts that did not alter the bi-layered structure of the hybrid. The temperature of the microenvironment surrounding the probe molecules was estimated from the emission lifetime analysis. The evidently reduced emission lifetimes in C3F-Azo-C6H/SSA and C3H-Azo-C6H/SSA hybrids in the film state, indicated the elevation of temperature of the microenvironment upon excitation of the chromophores, which demonstrated our previous hypothesis rationalizing that the high reactivity of isomerization in the hybrid film state is caused by heat trapping via multi-step dissipation of the excess energy. With the hybrid of a hydrocarbon analogue (C3H-Azo-C6H), a distinct difference in temperature gradient was found to show the crucial role of the perfluoroalkyl chain of the surfactant that traps the excess energy to retard its dissipation leading to three-dimensional morphological motion.

Novel amphiphilic graft block azobenzene-containing copolymer with polypeptide block: synthesis, self-assembly and photo-responsive behavior.

Well-defined amphiphilic graft block azobenzene-containing copolymer with polypeptide block was synthesized via a combination of copper-mediated atom transfer radical polymerization (ATRP), ring-opening polymerization and click reaction. The alkyne-terminated poly[6-(4-methoxy-azobenzene-4′-oxy)hexyl methacrylate] (PAzoMA) was synthesized by ATRP with a bromine-containing alkyne bifunctional initiator, and the azido-terminated poly(γ-2-chloroethyl-l-glutamate) (PCELG) was synthesized by ROP of γ-2-chloroethyl-l-glutamate-N-carboxyanhydride (CELG-NCA), then the two homopolymers were conjugated by click reaction to afford block azobenzene-containing copolymer PAzoMA-b-PCELG. The chloro groups in PCELG block were transformed into azido groups via azide reactions, and the alkyne-terminated MPEG was grafted to the polypeptide block to afford the final product PAzoMA-b-poly((l-glutamate)-graft-methoxy poly(ethylene glycol)) (PAzoMA-b-(PELG-g-MPEG)) by click reaction. Giant vesicles (micrometer size) were obtained from the amphiphilic graft block copolymer PAzoMA-b-(PELG-g-MPEG) through a solution self-assembly due to the rigid PAzoMA chains and polypeptide chains with the α-helical structure. The investigation of the photo-isomerization behavior of PAzoMA-b-(PELG-g-MPEG) in solution and in vesicular solution showed trans–cis isomerization in solution was quicker than that in vesicular solution and azobenzene J-aggregates in the vesicle solution were only observed. The formation mechanisms of the vesicles were also explored. The research results may provide guidelines for the study of complex copolymers containing different types of rigid chains.

Synthesis and Photodynamics of Stilbenyl‐Azopyrroles: Two‐Photon Controllable Photoswitching Systems

AbstractThree new stilbenyl‐azopyrroles 3 a–c were synthesized through a Mizoroki‐Heck C−C‐type coupling reaction between the 2‐(4′‐iodophenyl‐azo)‐N‐methyl pyrrole (1), and three different para‐substituted styrene derivatives. Inclusion of additional NO2 and NMe2 groups at the para‐position of the stilbenyl section resulted in significant changes of their linear and non‐linear optical properties. The photoisomerization behavior was studied through ultrafast laser techniques for single‐ and two‐photon excitation. The time‐resolved studies indicate that, despite the drastic changes in conjugation, the typical path for photoisomerization is maintained in these systems for both single and biphotonic excitation. In particular, the NO2 substituted molecule showed improved two‐photon absorption capacities, together with a significant trans−cis isomerization channel, implying that the photoswitching process can be controlled with high spatial precision through non‐linear optical excitation.

Synthesis and Photocontrolled Supramolecular Self-Assembly of Azobenzene-Functionalized Perylene Bisimide Derivatives.

Azobenzene (Azo) units were successfully introduced into perylene bisimide (PBI) structures in order to realize the photocontrolling of the morphology of the supramolecular assembly of PBI by a photoisomerization process. A total of three Azo-functionalized perylene bisimide derivatives (PBI1, PBI2, and PBI3) with different alkyl chain lengths were designed and synthesized by imidization of 3,4,9,10-perylene tetracarboxylic dianhydride with the corresponding amines. The structures of these compounds were characterized by proton nuclear magnetic resonance (1H NMR) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The photoisomerization behaviors of Azo units in PBIs were investigated using ultraviolet-visible (UV-VIS) absorption spectroscopy, which were obviously effected by solvents and the alkyl chain length. Furthermore, the photoisomerization of Azo units has the obviously regulatory effect on the morphology of supramolecular assembly of PBIs, especially for the medium-length alkyl chain-linked Azo-functionalized PBI derivative (PBI2). This research realized the photocontrolling of the morphology of the supramolecular assembly of PBI derivatives by photoisomerization of Azo units.

Photophysics and luminescence switching properties of a series of photochromic styrylbenzene-terpyridine conjugate: Experimental and DFT/TD-DFT investigation

Joint experimental and computational investigation have been carried out in this work with regard to photophysical and photo-isomerization behavior of a series of photochromic terpyridine derivatives covalently coupled with styrylbenzene unit. Several electron-donating and electron-accepting groups were incorporated in the compound, tpy-pvp-X (X = H, Me, Cl, NO2, and Ph) to tune their photophysical as well photo-isomerization behaviors. All the compounds underwent trans-to-cis isomerization upon interaction with UV light with substantial changes in their absorption and luminescence spectra. Reversal of cis to trans forms were also achieved upon interacting with visible light. Trans-to-cis isomerization leads quenching of luminescence, while backward cis-to-trans isomerization gives rise to restoration of the original luminescence. Thus, "on-off" and "off-on" emission switching was made possible upon alternate interaction of the compounds with UV and visible light. Interestingly, the photochromic and photo-isomerization behaviors of the compounds are strongly influenced by the presence of acid. Detailed kinetic and thermodynamic aspects of the photo-isomerization process were also addressed in this study.

Multiscale Study of the Relationship between Photoisomerization and Mechanical Behavior of Azo-Polymer Based on the Coarse-Grained Molecular Dynamics Simulation

Cross-linked liquid crystalline polymers (CLCPs) incorporated with photochromic azobenzene moieties can exhibit large and reversible deformations under the exposure of actinic lights. To practicall...

Synthesis of Polyazobenzenes Exhibiting Photoisomerization and Liquid Crystallinity.

While only a few studies have investigated the synthesis of main chain-type polyazobenzenes, they continue to draw an increasing amount of attention owing to their industrial applications in holography, dyes, and functional adhesives. In this study, dibromoazobenzene was prepared as a monomer for constructing azo-based π-conjugated polymers. Miyaura–Suzuki cross-coupling polymerization was conducted to develop copolymers containing an azobenzene unit as a photoisomerization block and a pyrimidine-based liquid crystal generator block. The prepared polymers exhibited thermotropic liquid crystallinity and underwent cis and trans photoisomerization upon irradiation with ultraviolet and visible light. Furthermore, the photoisomerization behavior was examined using optical absorption spectroscopy and synchrotron X-ray diffraction spectrometry.