CF® dye picolyl azide reacts with alkyne to form 1,2,3-triazole by 1,3-dipolar Huisgen cycloaddition through the use of a much lower copper (I) concentration without sacrificing reaction efficiency. CF® dyes are Biotium's line of next-generation fluorescent dyes with advantages in brightness, photostability, and conjugate specificity compared to other fluorescent dyes. • Green fluorescent CF®488A dye has excitation/emission at 490/515 nm. • Red fluorescent CF®568 dye has excitation/emission at 562/583 nm. • Deep-red fluorescent CF®594 dye has excitation/emission at 593/614 nm. • Far-red fluorescent CF®640R dye has excitation/emission at 642/662 nm. • Far-red fluorescent CF®647 dye has excitation/emission at 650/665 nm. • Far-red fluorescent CF®660C dye has excitation/emission at 667/685 nm. • Far-red fluorescent CF®660R dye has excitation/emission at 663/682 nm. • Far-red/near-IR fluorescent CF®680 dye has excitation/emission at 681/698 nm. • Far-red/near-IR fluorescent CF®680R dye has excitation/emission at 680/701 nm.