An iodine‐promoted one‐pot cascade oxidative annulation reaction has been developed for the synthesis of [1,2,3]triazolo[1,5‐a]quinolines from methyl azaarenes and N‐tosylhydrazines. The reaction has a broad substrate scope and can be easily scaled up to gram‐scale. 1,2,3‐Triazoles are an important skeletal structure for the construction of C−C and C−P bonds, 2‐cyclopropylquinolines and imidazo[1,5‐a]quinolines, for which different synthetic applications were explored.