3-(3-Methyl-3H-diazirin-3-yl)propanoic acid is primarily used in biochemical research as a photoactivatable crosslinking agent. Its diazirine group becomes highly reactive upon exposure to ultraviolet (UV) light, enabling it to form covalent bonds with nearby molecules. This property is particularly valuable in studying protein-protein interactions, ligand-receptor binding, and other molecular interactions. Researchers often incorporate it into probes or labels to capture transient or weak interactions that are difficult to detect using traditional methods. Additionally, it is utilized in the development of affinity-based probes for identifying and characterizing unknown binding partners in complex biological systems. Its application extends to mapping protein networks and understanding cellular processes at the molecular level.