Cy3-PEG7-exo-BCN is a derivative of the Cyanine 3 (Cy3) dye featuring seven PEG units. This compound includes a lipophilic bidentate macrocyclic ligand, BCN, which can be used for further synthesis of macrocyclic complexes. In click chemistry, exo-BCN reacts with azide-containing molecules to form stable triazoles without the need for a catalyst.