Meso-substituted 21,23-dithiaporhyrins were synthesized that self-assemble into columnar liquid crystalline phases. Furthermore, the porphyrins possess absorption profiles that span from 400 nm to 800 nm, undergo two reversible electrochemical redox reactions at approximately 465 and 670 mV vs. ferrocene/ferricenium and are electrochromic. Thin films of these dithiaporhyrins of approximately 60 nm thickness were formed by spin-casting methods from chloroform and were subjected to impedance spectroscopy. The pristine films showed very low conductivity at open circuit potentials (undoped); however, electrochemically p-doping resulted in stable films with four orders of magnitude higher conductivity.

Thiophene-containing porphyrin compounds are capable of catalytic, photo-reductive dehalogenation on an array of α-halo ketone model substrates with low catalyst loadings (0.1 mol%), in the presence of low energy, red light (>645 nm).

Three donor–acceptor–donor (D–A–D) pyrene chromophores are described and compared by DFT computations. The two properties of low energy photon absorption and low energy electrochemical reduction are demonstrated through a pyrene framework. Altering the electron‐acceptor strength of the pyrene core by chemical oxidation or installation of a thiadiazole dioxide heterocycle results in the formation of D–A–D chromophores with absorption bands up to 900 nm and LUMO energy levels of approximately –4.1 eV vs. vacuum.

Core-modified 21,23-dithiaporphyrins, meso-substituted with both electron-withdrawing 4-phenylcarboxylic acids and related butyl esters, and electron-donating phenyldodecyl ethers were synthesized. The porphyrins displayed broad absorbance profiles that spanned from 400 to 800 nm with molar absorptivities ranging from 2500 to 200000 M(-1) cm(-1). Electrochemical experiments showed the dithiaporphyrins undergo two consecutive, one-electron, quasi-reversible oxidations and reductions at -1.78, -1.43, 0.63, and 0.91 V versus a ferrocene/ferrocenium internal standard. Spectroelectrochemistry and cyclic voltammetry revealed the dithiaporphyrins are stable and can endure many cycles of oxidation and reduction without signs of decomposition. The electronics of the two dithiaporphyrins were similar, and DFT calculations showed the HOMO-LUMO energy difference was smaller than tetrapyrrolic porphyrin analogues. Overall, the combination of desirable electronics, namely: quasi-reversible oxidations and reductions as well as broad absorbance profiles, combined with stability, imply that these core-modified 21,23-dithiaporphyirns could be potentially used as an ambipolar material for organic electronic applications.

Saddle-shaped 21,23-dithiadiacenaphtho[1,2-c]porphyrin exhibits binding interaction with [60]fullerene in addition to photon absorption bands extending to 1000 nm.

21,23-Dithiaporphyrins were synthesized containing pi-extending ethynyl substituents at the meso positions. These porphyrins displayed highly bathochromic and broadened absorbance profiles spanning 400-900 nm with molar absorptivities ranging from 2500 to 300,000 M(-1) cm(-1). Electrochemically, these ethynyl dithiaporphyrins undergo a single oxidation at 0.44 or 0.57 V and reduction at -1.17 or -1.08 V versus a ferrocene/ferrocenium internal standard depending on the type of functionalization appended to the ethynyl group. DFT calculations predict that the delocalization of the frontier molecular orbitals should expand onto the meso positions of the ethynyl 21,23-dithiaporphyrins; shrinking the HOMO-LUMO energy gap by destabilizing the HOMO energy. Indeed, the DFT results agree with our optical and electrochemical assessments. Finally, differential scanning calorimetry combined with cross-polarized optical microscopy and powder X-ray diffraction was used to assess the ability of these porphyrins for long-range order. For the ethynylphenyl alkoxy 21,23-dithiaporphyin, birefringent, soft-crystalline-like domains were observed by polarized microscopy, which are marginally sustained by a low-level of crystallinity detected in the XRD, suggesting that long-range ordering is possible. Overall, ethynyl 21,23-dithiaporphyrins are able to harvest much lower energy light and possess lower oxidation and reduction potentials compared to their pyrrolic analogues, which are desirable properties for applications in organic electronics.

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