tert-Butyl 2,5-diazaspiro[3.5]nonane-2-carboxylate is primarily used in pharmaceutical research and development as a key intermediate in the synthesis of complex organic molecules. Its spirocyclic structure makes it valuable for constructing biologically active compounds, particularly in the design of drugs targeting neurological disorders and other therapeutic areas. The tert-butyl group provides stability and facilitates further chemical modifications, making it a versatile building block in medicinal chemistry. Additionally, it is employed in the development of novel ligands for catalysis and in the study of molecular interactions due to its unique structural features.