Synergistic integration of tetraphenylethylene π-bridge and localized asymmetric electron distribution for enhanced photocatalytic indole C-3 thiocyanation

The development of efficient photocatalytic covalent organic frameworks (COFs) remains challenged by rapid charge recombination and insufficient carrier utilization. Herein, we report BC-TAPE-COF, a covalent organic framework engineered with synergistic functional compartmentalization for photocatalytic indole thiocyanation. Its tetraphenylethylene (TPE) π-bridge served dual roles: activating oxygen and enhancing interlayer charge separation, while bicarbazole as localized asymmetric electron distribution (LAED) units drove exciton dissociation through intrinsic electron density gradients. This cooperative design strategy yielded a photocatalyst with unprecedented catalytic efficiency. BC-TAPE-COF can drive the photocatalytic indole C-3 thiocyanation with ultra-low loading and maintain structural integrity over multiple catalytic cycles.