Three‐Dimensional Covalent Thiazolo[5,4‐d]thiazole Frameworks with sur‐a Topology for Coupling Photoactivation of Oxygen and Biomass

Developing new topological three‐dimensional (3D) covalent organic framework (COF) structures with strong electron donor–acceptor (D–A) properties represents a promising approach for harvesting high‐performance photocatalysts. In this study, we developed two unprecedented 3D COFs with sur‐a topology by [3 + 2 + 4]‐c strategy. The formation of sur‐a topological structures relies on an elongated [3 + 2]‐c tetrahedral thiazolo[5,4‐d]thiazole (DTZ)‐based building block (DTZ‐CHO) with lower C 2 ‐symmetry. This unit is formed by inserting linear asymmetric DTZ subunit (2‐c vertex) between two 3‐c vertices. The incorporation of strong DTZ‐pyrene/vinyl electron D–A structures efficiently promote exciton separation and charge transfer during photocatalysis, thereby demonstrating high‐efficiency coupling photoactivation performance toward oxygen and biomass. It delivers a hydrogen peroxide photosynthesis rate of ∼12 092 µmol g −1 h −1 based on four‐step direct Yeager‐type oxygen photoreduction mechanism on DTZ active centers, pairing with efficient 5‐hydroxymethylfurfural photooxidation (∼10 264 µmol g −1 h −1 ). This work highlights the potential of topologically unique 3D COFs with robust D‐A structures as high‐efficiency photocatalysts for artificial photosynthesis.