A novel approach for the synthesis of diverse substituted imidazoles and quinoxalines via an iodine-promoted cyclization reaction is described. The methodology showcases a broad substrate scope, achieving moderate to very good yields for biologically relevant imidazoles and quinoxalines. Notably, iodine serves as both an iodinating agent and an oxidizing agent, as shown by a mechanistic study. The current methodology is capable of being scaled up to gram quantities, operates in a metal-free environment under mild reaction conditions, and utilizes readily available substrates.