Diethyl chlorophosphite is primarily used as a key intermediate in the synthesis of various organophosphorus compounds. It plays a significant role in the production of pesticides and insecticides, where it acts as a building block for creating active ingredients that target agricultural pests. Additionally, it is utilized in the preparation of flame retardants, which are incorporated into materials like plastics and textiles to enhance fire resistance. In the pharmaceutical industry, it serves as a reagent in the synthesis of certain drugs, particularly those involving phosphorus-containing molecules. Its reactivity also makes it valuable in organic synthesis for constructing complex chemical structures, especially in the development of ligands for catalysis. Due to its high reactivity, it should be handled with care in controlled environments.