This azadibenzocyclooctyne-tetramethyl rhodamine (TAMRA) derivative is a versatile fluorescent reagent for labeling azide containing molecules or compounds. Cyclooctynes are useful in strain-promoted copper-free azide-alkyne click chemistry reactions.This dibenzocyclooctyne will react with azide-functionalized compounds or biomolecules without the need for a Cu(I) catalyst to result in a stable triazole linkage. Subsequent labeled molecules can be visualized by fluorescence spectroscopy.