Diethylenetriamine is widely used as a curing agent for epoxy resins, where it acts as a hardener to improve mechanical strength, chemical resistance, and thermal stability of the final polymer product. It is also employed in the synthesis of chelating agents, such as EDTA and related derivatives, which are essential in water treatment, detergents, and metal deactivation in industrial processes. In agriculture, it serves as an intermediate in the production of herbicides and fungicides. Additionally, it finds use in gas treatment processes to remove acidic components like CO₂ and H₂S from natural gas and refinery streams. Its ability to form complexes with metal ions makes it valuable in catalysis and in the preparation of metal-organic frameworks.