Abstract: Simple and efficient photoacid generators (PAGs) for carboxylic and sulfonic acids based on N-acyl-N-phenylhydroxylamines have been demonstrated. Irradiation of o-carboxylates and thermally rearranged o-arenesulfonates of N-acyl-N-phenylhydroxylamines using UV light (≥254 nm) in aqueous methanolic solution resulted in efficient generation of carboxylic and sulfonic acids respectively. The carboxylic acid generation ability of N-acyl-N-phenylhydroxylamines was found to be dependent on their N-acyl substituents. Further, polymer bearing o-arenesulfonates of N-acyl-N-phenylhydroxylamine was synthesized and demonstrated as PAG for sulfonic acids.