2-[2-(prop-2-ynyloxy)ethoxy]-4-[3-(trifluoromethyl)-3H-diazirin-3-yl]benzoic acid is a trifunctional building block for chemical probe synthesis, typically employed for photoaffinity labeling in chemcial biology and medicinal chemistry. It contains a light-activated diazirine (photoreactive group), terminal alkyne tag (clickable handle), and carboxylic acid synthetic handle (connectivity group). When appended to a ligand or pharmacophore through its amine linker, this probe building block allows for UV light-induced covalent modification of a biological target with potential for downstream applications via the alkyne tag.
Cross-linking chemistry and biology: development of multifunctional photoaffinity probes. 
Simple and Versatile Method for Tagging Phenyldiazirine Photophores. 
Design and Synthesis of a Tag-Free Chemical Probe for Photoaffinity Labeling. 
Recent Progress in Diazirine-Based Photoaffinity Labeling.