Used as an intermediate in the synthesis of quinolone-based pharmaceutical compounds, particularly in the development of antibacterial drugs such as fluoroquinolones. Its 4-hydroxyquinoline-3-carboxylic acid ethyl ester core serves as a key building block for further chemical modifications to form bioactive molecules targeting bacterial infections. Commonly employed in medicinal chemistry for optimizing drug candidates against infectious diseases caused by bacteria. Also utilized in research settings to explore new therapeutic agents with enhanced efficacy, broader spectrum, and reduced antibiotic resistance.