New synthetic methodology has been developed for the synthesis of [1, 2-a] fused imidazoles and benzimidazoles using intramolecular homolytic aromatic substitution. In the intramolecular substitution, N-(ω-alkyl) radicals are generated using Bu3SnH from N-(ω- phenylselanyl) alkyl side chains. Phenylselanyl groups are used as radical leaving groups to avoid problems in the N-alkylation of imidazoles and benzimidazoles. Arylsulfones for ...