Formaminomalonic acid diethyl ester is primarily utilized in organic synthesis as a versatile intermediate. It serves as a key building block in the preparation of various heterocyclic compounds, particularly in the synthesis of pyrimidine derivatives, which are important in pharmaceutical and agrochemical industries. Its application extends to the development of nucleoside analogs, which are crucial in antiviral and anticancer drug research. Additionally, it is employed in the synthesis of amino acids and peptides, contributing to advancements in biochemistry and medicinal chemistry. The compound’s reactivity and functional groups make it valuable for constructing complex molecular structures in research and industrial settings.