Used primarily as a key intermediate in the synthesis of high-performance polymers, especially in the production of polyimides and polyamides. Its rigid aromatic structure and functional carboxylic acid groups enhance thermal stability and mechanical strength of the resulting polymers. Commonly applied in specialty engineering plastics and advanced composite materials for aerospace, electronics, and high-temperature environments. Also utilized in the development of proton exchange membranes for fuel cells due to its ability to provide controlled ion conductivity and chemical durability. Its derivatization supports the design of metal-organic frameworks (MOFs) for gas storage and separation applications.