Abstract: A number of more or less deactivated arenes, ArH, were effectively mono- or diiodinated with strongly electrophilic I+ reagents prepared from either diiodine or potassium iodide and with added sodium periodate, and reacted for 30 min at 25 – 30 °C in concd (min. 95%) sulfuric acid. The iodinating I+ solutions thus obtained were always applied in a 10% excess in respect to the reacted arenes, with using either the “direct” method or the “inverse” method of aromatic iodination explained in the text. The yields for the iodinated pure products varied from 17% to 91%.