Flamma® Black01 PEG4-Alkyne is a copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) reagent of universal dark quencher that the range of absorption covers from 400 to 800 nm with no native fluorescence. Black01 quencher displays high absorption coefficient, superb stability and aqueous solubility. PEG4-alkyne couples with an azide to form 1,4-disubstituted 1,2,3-triazole, and prior to perform CuAAC, the azide should be introduced to the probe or counterpart biomolecule by means of chemical or genetic modification. We offer qFlamma® Black01 PEG4-alkyne as a click chemistry reagent in designing probes consisting of spectrally paired fluorophore and quencher for multiplexed bio-analysis and nucleic acid hybridization.