4-((4-Ethoxyphenyl)amino)-4-oxobutanoic acid is primarily utilized in organic synthesis and pharmaceutical research. It serves as a key intermediate in the development of various bioactive compounds, particularly those targeting therapeutic applications. Its structure, featuring both amide and carboxylic acid functional groups, makes it valuable for designing molecules with specific biological activities. Researchers often employ it in the synthesis of potential drug candidates, especially in areas like anti-inflammatory or analgesic agents, due to its ability to interact with biological targets. Additionally, it may be used in the study of enzyme inhibition or as a building block for more complex chemical entities in medicinal chemistry.