Isophthalic acid is widely used in the production of unsaturated polyester resins, which are essential in manufacturing fiberglass-reinforced plastics. These plastics are applied in the construction of boats, automotive parts, and storage tanks due to their durability and resistance to corrosion. It also serves as a key component in the synthesis of coatings and paints, providing excellent adhesion, chemical resistance, and weatherability. Additionally, it is utilized in the production of high-performance polymers, such as polyesters and polyamides, which are used in textiles, packaging, and engineering plastics. Its role in improving the thermal stability and mechanical properties of materials makes it valuable in various industrial applications.