1,4-Dibenzyl-1,4-diazoniabicyclo[2.2.2]octane dichloroiodate is an efficient and regioselective reagent for iodination of aryl amines. A wide variety of aryl amines in reaction with this reagent afforded regioselectively iodinated products. The iodination reaction can be carried out in solution or under solvent-free condition at room temperature.