Used primarily as a photoactivatable crosslinking agent in biochemical and proteomic research. Its main application lies in studying protein-protein interactions and mapping binding sites. Upon exposure to UV light, the diazirine group generates highly reactive carbenes that insert covalently into nearby C–H, N–H, or O–H bonds, enabling irreversible crosslinking between interacting biomolecules. The NHS ester end reacts efficiently with primary amines on proteins or peptides, allowing site-specific labeling. The spacer arm provides flexibility and can help reduce steric hindrance. Commonly employed in pull-down assays, affinity labeling, and structural biology to capture transient or weak interactions that are difficult to study with conventional methods. Also useful in photoaffinity labeling to identify drug targets or receptor-ligand interactions. Stable under storage conditions but reacts rapidly under controlled experimental settings, making it a valuable tool for probing complex biological systems.