Used as an intermediate in the synthesis of cetirizine, a second-generation antihistamine. It plays a key role in pharmaceutical manufacturing processes where esterification helps improve lipophilicity, aiding in the absorption and bioavailability of the final drug. The methyl ester derivative is often employed in research settings to develop more effective antihistaminic agents with reduced side effects. It is not used directly as a therapeutic agent but serves as a crucial precursor in the production of active pharmaceutical ingredients.