The study commenced by investigating suitable conditions for the synthesis of diaryliodonium salts 3 from the corresponding ortho-iodoazobenzenes 1. With this type of iodoarene, our standard one-pot conditions with mCPBA and triflic acid or tosic acid and a suitable arene failed, 27b, 27c as did one-pot reactions of 1 with arylboronic acids. 27d To our delight, a sequential onepot reaction 27e, 27f, 30 with initial oxidation of iodoarene 1 using mCPBA and tosic acid at 40 °C, followed by addition of arene 2 at room temperature proved to be successful for the synthesis of the novel iodonium salts 3 (Scheme 2). In this way, the otherwise unsubstituted ortho-azobenzene iodonium salt 3a was obtained in 84% isolated yield from 1a. A stepwise synthesis of 3a with isolation of the corresponding [hydroxy(tosyloxy)iodo]arene before treatment with anisole yielded the product in 78% overall yield. Anion exchange of 3a to the corresponding triflate salt 3a' could be performed by in situ treatment with triflic acid or by workup with NaOTf. The scope investigations were focused on synthesis of unsymmetric diaryliodonium salts (Ar 1 Ar 2 IX) to avoid wasting a precious azobenzene moiety in the subsequent arylations. Previous studies have demonstrated that anisyl and trimethoxyphenyl (TMP) moieties are efficient "dummy groups" in chemoselective arylations with Ar 1 Ar 2 IX under metal-free conditions. To the contrary, a mesityl dummy group is more suitable to achieve selective aryl transfer under metal-catalyzed conditions. The anisyl dummy group was selected as the standard, and substituted ortho-iodoazobenzenes 1b-d were reacted with anisole to provide iodonium salts 3a-d in good to high yields. Substituents were well tolerated on the para-azo aryl moiety, with bromo-substituted salt 3b well positioned for further latestage functionalizations. Further substituents on the iodosubstituted aryl group were also tolerated, as shown by methylsubstituted product 3d. Furthermore, mesitylene and trimethoxybenzene could be utilized in the synthesis to provide iodonium salts 3e and 3f bearing a mesityl or TMP dummy group. Surprisingly, we could also obtain bis(diaryliodonium) salt 3g in good yield through double functionalization of the corresponding diiodoazobenzene 1e. All products were selectively obtained as the E-isomer, and easily isolated through precipitation.