Post‐Synthetic Modification of 2D Covalent Organic Frameworks With B←N Coordination Bonds for Efficient Photocatalysis

ABSTRACT The development of highly efficient covalent organic frameworks (COFs)‐based photocatalysts remains significantly challenged by their limited light absorption range and rapid recombination of photogenerated charge carriers. Herein, a post‐synthetic modification method was reported for tailoring the structure and functionality of COFs‐based photocatalysts, successfully incorporating boron‐nitrogen (B←N) coordination units into imine‐linked COFs to construct BNCOF‐1 and BNCOF‐2 with enhanced photocatalytic properties. Theoretical calculations demonstrate that incorporating B←N coordination units markedly reduce the lowest unoccupied crystal orbital (LUCO) energy level. This reduction narrows the bandgap and strengthens the built‐in electric field, thereby effectively facilitating the separation of photogenerated charge carriers. The BNCOF‐n materials exhibit substantially superior catalytic activity for photocatalytic aerobic oxidation reactions and excellent cycling stability compared to their parent COFs. This work confirms the effectiveness of the B←N coordination‐based post‐synthetic modification strategy in regulating the optoelectronic properties of COFs, providing a novel approach for designing highly stable and high‐performance heterogeneous photocatalysts.