Quasi‐Homogeneous Photocatalytic C─H Functionalization Enabled by Donor–Acceptor Microporous Polymer Aerogels Featuring Ultralong‐Lived and Long‐Range Excitons

Abstract Simultaneous promotion of charge and mass transportation between catalytic centers and reactants is crucial for photocatalysis but remains a substantial challenge on account of the widespread use of homogeneous or heterogeneous photocatalysts that suffer from sluggish reactant‐diffusion kinetics or interfacial electron‐transport resistance, respectively. Herein, we demonstrate the construction of conjugated microporous polymer aerogels as available quasi‐homogeneous photocatalysts by integrating structural designability, which allows for the incorporation of electron‐acceptor building blocks featuring ultralong‐lived excitons as high‐concentration local catalytic centers, and hierarchically porous gel networks that wrap solvent and reactants to provide a “single” reaction phase without interfacial resistance. A total of 18 samples of C─H functionalization reactions underpinned by four different mechanisms were screened to showcase the general applicability of the obtained aerogel photocatalysts, which achieved remarkable conversion efficiencies, gram‐scale productivities, and recyclability. By combining a designable structure for photophysical properties with hierarchical porosities for optimal charge/mass transfer, we believe microporous polymer aerogels can serve as a versatile design platform for quasi‐homogeneously photocatalyzing challenging reactions.