Abstract In contrast to published results, tetraalkylammonium dichloroiodates (Alk 4 N+ ICl 2- ) cannot be iodinating reagents for arenes in solvent-free conditions. Nevertheless, tetraalkylammonium dichloroiodates in sulfuric acid solutions or in the presence of Ag 2 SO 4 in H 2 SO 4 possess superelectrophilic properties and act as very convenient and efficient iodinating agents for deactivated arenes.