4,4'-Methylenebis(2-ethylbenzenamine) is primarily used as a curing agent in the production of epoxy resins. It helps in enhancing the thermal stability, mechanical strength, and chemical resistance of the final epoxy products. This chemical is also employed in the manufacturing of polyurethane foams, where it acts as a chain extender, improving the material's durability and flexibility. Additionally, it finds application in the synthesis of dyes and pigments, contributing to the colorfastness and stability of these compounds. Its role in the production of high-performance coatings and adhesives is significant, providing robust and long-lasting bonding solutions for various industrial applications.