Catalyst‐Free, Light‐Induced Three‐Component Reactions: Recent Advances and Mechanistic Insights

Catalyst‐free, light‐induced three‐component reactions can conveniently synthesize complex compounds. These elements align with the principles of green chemistry and have been research hotspots. Their combination not only simplifies the reaction but also avoids metal residues in the products. Previous reviews have focused mainly on single reactions, with little attention to the combination of all three. This review mainly focuses on recent advances (2015–2025) categorized by product types. Mechanisms and the roles of added reagents will be discussed. Key intermediates can be generated via electron donor–acceptor (EDA) complexes, single‐electron transfer, halogen atom transfer, hydrogen atom transfer, homolysis, singlet oxygen ( 1 O 2 ), triplet diradical species, carbenes, etc. Reactions via EDA complexes, which proceed under visible light, have attracted the most attention due to their practicality and simplicity. The discussion covers strategies for constructing CC, CN, CO, CS, and CSe bonds. We hope this review will be helpful for future research in this area.