Recent Advances in Photocatalyst Design for C-N Coupling Reactions: From Structure-Performance Relationships to Mechanistic Insights

Nitrogen-containing organic compounds are the cornerstone of life and modern industry. They are essential to all living organisms, constitute the active cores of numerous pharmaceuticals, and underpin a wide range of materials for daily use. Constructing C-N bonds has always been an indispensable part in the development of modern civilization. Conventional methods, however, often suffer from poor selectivity, harsh conditions, high energy intensity, poor atom economy and substantial pollutant generation. Heterogeneous photocatalysis, by contrast, offers a mild, precise, and environmentally benign alternative. This review concentrates on the recent progress in photocatalytic synthesis of key nitrogen-containing organics such as urea, amides, amines, imines, and amino acids. It systematically discusses the design of high-performance photocatalysts, the elucidation of structure-performance relationships, and underlying reaction mechanisms. In particular, the intrinsic logical connections among "design concept→structural feature→performance breakthrough→mechanistic understanding" across different catalytic systems are systematically compared and clarified. Finally, we emphasize that deepening fundamental research on key scientific questions, combined with application-oriented engineering exploration, will pave the way for the green, efficient, and sustainable production of nitrogen-containing chemicals.