AF 568 azide is an azide derivative of the orange fluorescent dye AF 568. It has an absorption wavelength range of 590-720 nm (FRET) and an emission wavelength range of 515-720 nm. AF 568 alkyne can undergo a copper-catalyzed azide-alkyne cycloaddition reaction (CuAAc) with molecules containing an alkyne group. It can also participate in strain-promoted alkyne-azide cycloaddition (SPAAC) with molecules that have DBCO or BCN groups, enabling specific coupling and labeling of biomolecules.