Used primarily as a key intermediate in the synthesis of second-generation antihistamines, such as Cetirizine and Levocetirizine, which are H1 receptor antagonists effective against allergic reactions with minimal sedative effects. The structure features a piperazine ring substituted with a (4-chlorophenyl)(phenyl)methyl group and an ethanol side chain, facilitating further modifications to enhance receptor selectivity and pharmacokinetic properties. It is also utilized in research for developing other piperazine-based therapeutics targeting histamine-mediated responses.