qFlamma^® Black01 Azide is a click chemistry reagent of universal dark quencher. Black01 quencher displays high absorption coefficient, superb stability and aqueous solubility, and the absorption range covers from 400 to 800 nm with no native fluorescence. Black01 azide can be used in both copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) and strain-promoted azide-alkyne cycloaddition (SPAAC). In both reactions, the azide couples with an alkyne to form 1,4-disubstituted 1,2,3-triazole. Prior to perform the coupling, an alkyne should be introduced to the probe or counterpart biomolecule by means of chemical or genetic modification. We offer qFlamma^® Black01 Azide as a click chemistry reagent for designing probes consisting spectrally paired fluorophore and quencher.