Diethyl (4-aminophenyl)phosphonate is primarily used as an intermediate in organic synthesis, particularly in the production of pharmaceuticals and agrochemicals. Its structure allows it to participate in various chemical reactions, making it valuable for creating complex molecules. In medicinal chemistry, it is utilized to develop compounds with potential therapeutic properties, such as antiviral or anticancer agents. Additionally, it serves as a key building block in the synthesis of phosphonate-based polymers and materials, which are employed in coatings, adhesives, and flame retardants. Its role in research and development highlights its importance in advancing chemical innovation and industrial applications.