Integrating Tetrathiafulvalene and Nickel‐Bis(dithiolene) Units into Donor‐Acceptor Covalent Organic Frameworks for Stable and Efficient Photothermal Conversion

Tetrathiafulvalene (TTF) and Ni‐bis(dithiolene) are typical conductive units widely studied in electronics, optics, and photochemistry. However, their applications in near‐infrared (NIR) photothermal conversion are often limited by insufficient NIR absorption and low chemical/thermal stability. Herein, we integrate TTF and Ni‐bis(dithiolene) into a covalent organic framework (COF) with stable and efficient NIR and solar photothermal conversion performance. Two isostructural COFs, namely Ni‐TTF and TTF‐TTF, are successfully isolated which are composed of TTF and Ni‐bis(dithiolene) units as donor‐acceptor (D−A) pairs or TTF units only. Both COFs show high BET surface areas and good chemical/thermal stability. Notably, compared with TTF‐TTF, the periodic D−A arrangement in Ni‐TTF significantly lowers the bandgap, leading to unprecedented NIR and solar photothermal conversion performance. The combination of tetrathiafulvalene and Ni‐bis(dithiolene) units gives rise to a donor‐acceptor covalent organic framework with high chemical/thermal stability and efficient near‐infrared/solar photothermal conversion performance.