Phenylmaleic anhydride is primarily used in the synthesis of polymers and resins, where it acts as a key intermediate. Its ability to form copolymers makes it valuable in creating materials with specific thermal and mechanical properties, often used in coatings and adhesives. Additionally, it serves as a building block in organic synthesis, particularly in the preparation of pharmaceuticals and agrochemicals, due to its reactive anhydride group. In research, it is utilized for studying Diels-Alder reactions, contributing to advancements in synthetic chemistry.