Furthermore, it should be emphasized that in case of diaryliodazinium triflate 2a a significant π-coordination of the tosyl arene ring to the I(III) center was observed (3.6 Å). To demonstrate the utilization of these novel iodonium salts as reactive synthetic building blocks and to get further insights into their reactivity, a variety of derivatizations were investigated (Scheme 4). Copper-catalyzed ring opening of the diphenyliodaoxinium triflate 1a with TBAI yielded the desired diiodo derivate 8 in 73% yield. Counterion exchange was achieved by treating a hot solution of the triflate derivate with an aqueous solution of KBr. Subsequent thermolysis of the resulting bromide salt resulted in the formation of 9 in 49% yield. The copper-catalyzed acidic ring opening of 1a with acetate yielded the monofunctionalized derivate 10 in 94%.