Diphenyliodonium bromide is widely used as a photoinitiator in the production of polymers and coatings, particularly in UV-curable systems. It facilitates the rapid polymerization of monomers and oligomers under UV light, making it essential in industries like electronics, where it helps in the fabrication of printed circuit boards and photoresists. Additionally, it is employed in dental materials for curing composite resins, ensuring quick and efficient hardening. Its role in organic synthesis as a reagent for introducing phenyl groups into molecules is also notable, aiding in the development of pharmaceuticals and specialty chemicals.