External Stimuli Responsive 2D Charge Transfer Polymers

2D conjugated charge‐transfer polymers hold the fundamental importance of both atomically defined molecular structures and unique spatial confinement for distinctive and exotic material properties. However, such 2D crystalline networks exhibit a fundamental processing challenge in polymer science and molecular assembly, which precludes emerging applications for 2D polymers. Here, an operationally simple solvothermal crystallization of conjugated charge‐transfer polymer into a freestanding and ultrathin 2D nanosheet directed by electrostatic recognition, π–π interaction, and charge‐transfer complexation is reported. High flexibility and 3D stacking capability of ultrathin 2D conjugated polymers provide a robust solution‐processing platform to uncover their emerging optoelectronics and multisensing capabilities. Resembling covalent organic framework assembly, these materials potentially open up a new exciting field of 2D conjugated networks with the structure flexibility and materials‐by‐design opportunities for all organic electronics.