When arene 2 is sensitive to acidic or oxidative conditions, it can be preferable to isolate the iodine(III) reagent 5 prior to the reaction with 2 according to Route C (Scheme 1). This strategy is also convenient when a scope of diaryliodonium salts using the same iodoarene 1 is to be prepared. By combining the conditions of Route A (ArI, ArH, m-CPBA and TsOH) with the step-wise strategy of Route C, diaryliodonium tosylates 3-OTs with an electron deficient Ar 1 -group can be synthesized via isolation of [hydroxy(tosyloxy)iodo]arenes (Koser's reagents, 7).