Diethyl (2-cyanoethyl)phosphonate is primarily used as a key intermediate in the synthesis of various organic compounds. It plays a significant role in the production of flame retardants, where it helps in enhancing the fire resistance of materials such as plastics, textiles, and coatings. Additionally, this chemical is utilized in the preparation of pharmaceuticals, particularly in the development of antiviral and anticancer agents. Its application extends to the field of agrochemicals, where it is involved in the synthesis of pesticides and herbicides, contributing to improved crop protection. Furthermore, it is employed in organic synthesis for constructing complex molecules, including phosphonates, which are valuable in medicinal chemistry and material science.