AbFluor™ dyes are a series of highly water-soluble fluorescent dyes spanning the visible and near-infrared spectrum for Labeling biomolecules, especially proteins and nucleic acids. AbFluor™ dyes bear the core structures of different fluorescent dye core structures that cover the fluorescence spectrum from UV to NIR. Innovative modifications to the core structure makes AbFluor™ dyes superior to other commercial dyes with many innovative novel features. AbFluor™ 680 is an outstanding 680 nm-excitable dye with the ?Ex/?Em of 681/698 nm, which is super alternative to Cy5.5, Alexa Fluor 680. It is the brightest among spectrally similar 680 nm dyes. It yields biologically more specific antibody conjugates and less background.