Photocatalytic, Electrocatalytic, and Photoelectrocatalytic Radical‐Mediated Three‐Component Cascade Cyclization Reactions: Facile Access to <i>N</i> ‐Heterocyclic Compounds

N ‐Heterocyclic compounds (NHCs) are widely encountered in natural products and pharmaceuticals with diverse biological activities, and constitute fundamental structural motifs in numerous organic compounds. Consequently, investigations into the synthesis and modification of these NHCs hold particular significance for chemists and pharmacologists. Of particularly note, multicomponents cascade cyclization reactions allow for creation of many bonds, even stereocenters, in a single step while maintaining predictable stereochemistry have drawn increasing interest, and its broader application has been reinforced by radical chemistry. Photocatalysis and electrocatalysis are two powerful strategies to promote the chemical reactions that have received tremendous attention in recent years. Moreover, photoelectrochemical, a fusion of electrochemical and photochemical, completes reactions that were once challenging, stands out as an effective tool. In these ways, a number of diversly NHCs are constructed. Herein, the most recent contributions on photocatalytic, electrocatalytic, and photoelectrocatalytic radical‐mediated three‐component cascade cyclization reactions to access NHCs are reviewed, providing more possible avenues for future work in this growing area.