Combinatorial Design of Benzodithiophene–Benzothiadiazole Building Blocks for Ultralarge Pore Optoelectronically Tunable Covalent Organic Frameworks

While covalent organic frameworks (COFs) have attracted enormous attention in diverse fields due to their large molecular design space, tuning their optoelectronic properties is challenging because of complex synthetic pathways. Herein, we establish a combinatorial synthetic strategy employing reactive donor and acceptor modules for the generation of extended linear COF building blocks, which already encode the key optoelectronic features of corresponding COFs. This approach enables optoelectronic functionality to be rationally preprogrammed at the building-block level, allowing systematic control over conjugation length, donor-acceptor composition, and energy-level alignment in the resulting COFs. As a great diversity of COFs can be generated from linear building blocks and easily accessible multifunctional nodes, this strategy offers a novel entry into the synthesis of numerous COFs with tunable optoelectronic properties and enables us to construct highly crystalline and porous photoactive COFs and oriented COF films. These pore systems allow for the inclusion of fullerene acceptor phases and the construction of periodic bulk heterojunctions, offering a blueprint for generating novel COFs with emerging optoelectronic features and device architectures.