Diphenyliodonium p-toluenesulfonate is widely used as a photoacid generator in photolithography processes, particularly in the production of semiconductors and microelectronics. It plays a critical role in generating acid upon exposure to UV light, which helps in the patterning of photoresists. Additionally, it is utilized in the synthesis of organic compounds, serving as a catalyst or reagent in various chemical reactions, including polymerization and cross-linking processes. Its ability to initiate cationic polymerization makes it valuable in coatings, adhesives, and advanced material development. The compound is also employed in research for studying reaction mechanisms involving cationic intermediates.