Modular establishment of a diketopyrrolopyrrole-based polymer library via Pd-catalyzed direct C-H (Hetero)arylation: a highly efficient approach to discover low-bandgap polymers.

A concise, highly efficient palladium-catalyzed direct C-H (hetero)arylation is developed to modularly assemble a diketopyrrolopyrrole (DTDPP)-based polymer library to screen low-bandgap and near-infrared (NIR) absorbing materials. The DTDPP-based copolymers P1 and P2 with an alternating donor-acceptor-donor-acceptor (D-A-D-A) sequence and the homopolymer P9 exhibit planarity and excellent π-conjugation, which lead to low bandgaps (down to 1.22 eV) as well as strong and broad NIR absorption bands (up to 1000 nm).