Isophthalic acid is used as an intermediate for high performance unsaturated polyesters, resins for coatings, high solids paints, gel coats and modifier of polyethylene terephthalate for bottles. It acts as precursors for the fire-resistant material nomex as well as used in the preparation of high-performance polymer polybenzimidazole. It is also employed as an input for the production of insulation materials.