Several new iodonium salts containing weakly coordinating anions were synthesized and characterized. Upon UV irradiation, the rates of photoacid generation in acetonitrile and their preliminary activity in the photopolymerization of epoxy silicones were compared. Studies showed those salts to be excellent photoacid generators. The anions [(C6F5)(3)B-C3H3N2-B(C6F5)(3)](-), B(C6F5)(4)(-), and Ga(C6F5)(4)(-) were more active and the compounds made from them more soluble in most solvents. The [(C6F5)(3)B-C6F4-B(C6F5)(3)](2-) anion was less active, and the compounds made from them were less soluble than compounds made from the three aforementioned anions. Compounds containing hexabromocarborane anion were quite similar to compounds containing SbF6- in both photoactivity and solubility.