Sulforhodamine 101 (commonly known as Texas Red(R)) based Dibenzylcyclooctyne-Fluor 585 probe emits at a longer wavelength than does either tetramethylrhodamine or LissamineTM rhodamine B conjugates. Unlike other rhodamine based probes, the Dibenzylcyclooctyne-Fluor 585 exhibits very little spectral overlap with flourescein. With peak absorption at 584 nm, Dibenzylcyclooctyne-Fluor 585 probe is particularly well suited for excitation by the 568 nm spectral line of the Ar – Kr mixed gas laser commonly used in many confocal laser-scanning microscopes or the 594 nm spectral line of the orange He-Ne laser. The fluorescence quantum yield of Dibenzylcyclooctyne-Fluor 585 probe is higher than that of tetramethylrhodamine or LissamineTM rhodamine B. Usually, conjugates of Dibenzylcyclooctyne-Fluor 585 probe exhibit higher fluorescence intensity than conjugates of other rhodamine based probes.