Steering Charge Transfer in Isostructural kgd Covalent Organic Frameworks via π‐Bridge Modulation for Overall H 2 O 2 Photoproduction

ABSTRACT While the donor‐π‐acceptor (D‐π‐A) architecture in covalent organic frameworks (COFs) facilitates charge separation for photocatalysis, overcoming rapid charge recombination remains a formidable challenge. Herein, we report a π‐bridge modulation strategy to precisely tailor intramolecular charge transfer dynamics in kgd COFs, enabling highly efficient H 2 O 2 photogeneration. By inserting vinyl, benzene, or thiophene spacers between hexabenzotriphenylene donors and triazine acceptors, three isostructural 2D COFs with systematically varied π‐bridges were constructed. Remarkably, the vinyl‐bridged HAV‐COF achieves an exceptional H 2 O 2 evolution rate of 10.5 mmol g −1 h −1 in pure water, significantly outperforming its aromatic analogues. Theoretical analyses reveal that the non‐aromatic vinyl bridge endows HAV‐COF with enhanced coplanarity and local dipole moment compared to the aromatic‐bridged counterparts. Consequently, this robust built‐in electric field drives directional carrier migration and maximizes electron‐hole spatial separation, resulting in the most effective suppression of charge recombination among the three studied COFs. Synergistically, the optimized electronic structure substantially lowers the thermodynamic energy barriers for *OOH and *OH intermediate formation during H 2 O 2 photoproduction. This study establishes non‐aromatic π‐bridges as superior charge transfer mediators in COF photocatalysts, providing design principles for high‐performance artificial photosynthesis systems.