Constructing Substituted‐Pyridine‐Linked Conjugated Porous Polymers via Multicomponent Hantzsch‐Type Reaction for Efficient Hydrogen Peroxide Photosynthesis from Real Seawater and Air

ABSTRACT Conjugated porous polymers (CPPs) have emerged as promising organo‐based semiconducting materials for solar‐to‐chemical energy conversion due to their customizable structures and functionalities. Exploring diverse synthetic routes provides a strong driving force to promote the development of this intriguing class of photocatalysts. Herein, we report a multicomponent reaction (MCR)‐based strategy to construct photoactive CPPs with precisely engineered donor–acceptor architectures. Utilizing a Hantzsch‐type three‐component condensation, a new family of pyridine‐3,5‐dicarbonitrile‐linked CPPs (HCPPs) was synthesized, wherein β‐ketonitrile‐derived building units are strategically incorporated to generate electron‐deficient heterocyclic linkages that serve as intrinsic acceptors. The resulting materials exhibit exceptional photophysical properties and enable efficient non‐sacrificial hydrogen peroxide (H 2 O 2 ) photosynthesis. Notably, HCPP‐1, bearing a thiophene‐based donor, achieves a remarkable H 2 O 2 production rate of 5230 µmol g −1 h −1 under visible light in pure water/oxygen, and maintains high performance (4850 µmol g −1 h −1 ) even under simulated sunlight using real seawater and ambient air, outperforming the vast majority of reported photocatalysts. Mechanistic studies reveal spatially separated redox centers that synergistically drive an indirect two‐electron oxygen reduction reaction (ORR) and a four‐electron water oxidation reaction (WOR). This MCR‐enabled design opens a general avenue to functional porous semiconductors for advanced solar fuel applications.