Used as an intermediate in organic synthesis, particularly in the preparation of pharmaceuticals and fine chemicals. Its reactive anhydride group allows for easy ring-opening and functionalization, making it valuable in constructing complex cyclic or polycyclic structures. Commonly employed in the development of active pharmaceutical ingredients (APIs) where a five-membered ring scaffold is required. Also utilized in polymer chemistry to introduce cyclic moieties into polymer chains, enhancing thermal or mechanical properties. Its ability to form derivatives with amines and alcohols makes it suitable for creating specialty esters and amides in agrochemicals and performance materials.