Diethyl (chloromethyl)phosphonate is primarily used as an intermediate in the synthesis of various organic compounds, particularly in the production of flame retardants and plasticizers. Its role in the creation of phosphorus-containing polymers enhances the fire resistance of materials, making it valuable in industries such as textiles, electronics, and construction. Additionally, it serves as a key reagent in organic synthesis, facilitating the introduction of phosphonate groups into molecules, which is crucial in the development of pharmaceuticals and agrochemicals. Its reactivity with nucleophiles also makes it useful in the preparation of biologically active compounds and specialty chemicals.