Used in photoaffinity labeling studies to identify and map protein-ligand interactions. Upon exposure to UV light, the diazirine group generates highly reactive carbenes that insert covalently into nearby C–H, O–H, or N–H bonds, allowing stable crosslinking between biomolecules. This enables researchers to capture transient interactions in complex biological systems, such as enzyme-substrate or receptor-ligand binding, for downstream analysis by mass spectrometry or gel electrophoresis. Particularly valuable in proteomics for target identification and binding site mapping.