Herein, we report an efficient route for coumarin C3‐C4 fused imidazole scaffolds via indium chloride‐mediated single‐step
transformation of 4‐azido‐coumarin with amines/aldehydes and coumarin C3‐C4 fused 5‐substituted‐1,4‐benzodiazepine scaffolds
with 1,2‐azide‐nitrogen migration through two‐step sequential synthesis via the transitory intermediacy of 2,3‐bridged‐2H‐azirine. A
plausible mechanistic pathway has been proposed from the control/entrapment experiments and 1H‐NMR studies. This protocol
provides the reaction condition‐dependent product selectivity, structural diversification, and excellent yields.