AF488 azide is a fluorescent dye used to assess the reactivity of immobilized DIBO groups. It has an azide group that can undergo a copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC) with molecules containing an alkyne group. It can also participate in a strain-promoted azide-alkyne cycloaddition reaction (SPAAC) with molecules containing DBCO or BCN groups. The emission (λem) and excitation (λex) wavelengths of AF488 are 520 nm and 470 nm, respectively.