Cy5 5 alkyne non-sulfonated is a near-infrared fluorescent cyanine derivative equipped with an alkyne functional group for click chemistry applications Through copper-catalyzed azide-alkyne cycloaddition (CuAAC) it forms covalent conjugates with azide-containing biomolecules metabolites or small-molecule ligands Cy5 5 alkyne non-sulfonated is primarily soluble in organic solvents aqueous solutions containing organic co-solvent such as DMSO may be used during conjugation Based on these chemical properties Cy5 5 alkyne non-sulfonated holds research potential in labeling nucleic acids peptides proteins lipids and other biomolecules for biomedical imaging tissue distribution evaluation and related pharmaceutical research applications