Product Description: Cy5-PEG3-endo-BCN is a dye derivative of Cyanine 5 (Cy5) (HY-D0821) containing 3 PEG units. Cy5-PEG3-endo-BCN contains the lyophilic bidentate macrocyclic ligand endo-BCN, which can further synthesize macrocyclic complexes. In click chemistry, endo-BCN can react with molecules containing azide groups to form stable triazoles in the absence of catalysts.