Used primarily as a key intermediate in the synthesis of varenicline, a medication for smoking cessation. It plays a critical role in constructing the core structure of varenicline due to its functional groups, which allow for selective chemical transformations. The nitro group enables reduction to an amine, facilitating further coupling reactions, while the piperidinyl-oxygen linkage contributes to the molecule’s affinity for nicotinic acetylcholine receptors. Its hydrochloride salt form enhances stability and solubility, making it suitable for use in pharmaceutical manufacturing processes.