Sodium O,O-diethyl phosphorothioate is primarily used as an intermediate in the synthesis of organophosphate pesticides. It plays a crucial role in the production of insecticides that are effective against a wide range of agricultural pests. These insecticides help protect crops from damage, ensuring higher yields and better quality produce. Additionally, it is utilized in research and development for creating new chemical compounds with potential applications in pest control. Its effectiveness in these applications makes it a valuable component in the agricultural and chemical industries.