[structure: see text] A polyfluorinated cyanine dye has been synthesized and characterized. Compared with the nonfluorinated analogue, the dye exhibits significantly reduced aggregation in aqueous media, enhanced fluorescence quantum yield, greater resistance to photobleaching upon direct irradiation, and reduced reactivity toward singlet oxygen. All of these properties are favorable for use of cyanine dyes as fluorescent labels and point toward fluorination as a general strategy for improving performance in imaging applications.