Intrareticular Exciton Effects Regulate Photocatalytic Activity in Donor–Acceptor Olefin‐Linked Covalent Organic Frameworks

Abstract Olefin‐linked covalent organic frameworks (OL‐COFs) show great promise for visible‐light‐driven photocatalysis. Manipulating atomic‐level donor–acceptor interactions in OL‐COFs is key to understanding their exciton effects in this system. Here, three OL‐COFs are presented with orthorhombic lattice structures, synthesized via Knoevenagel polycondensation reaction of terephthalaldehyde and tetratopic monomers featuring phenyl, benzo[c][1,2,5]oxadiazole, and benzo[c][1,2,5]thiadiazole moieties. These OL‐COFs feature tunable donor–acceptor interactions, making them ideal for studying exciton effects in olefin‐linked systems. Comprehensive analyses, including temperature‐dependent photoluminescence spectra, ultrafast spectroscopy, and theoretical calculations, reveal that stronger donor–acceptor interactions lead to reduced exciton binding energy ( E b ), accelerated exciton dissociation, and longer‐lived photogenerated charges, thereby enhancing photocatalytic performance. Notably, The TMO‐BDA COF, with the lowest E b , demonstrates superior photocatalytic activity in one‐pot sequential organic transformation and excellent catalytic performance in gram‐scale reactions, highlighting its potential for practical applications. This work provides valuable insights into regulating the exciton effect at the molecular level in OL‐COFs, offering pathways to enhance photocatalytic efficiency.