Near-IR Cf dyes are a group of fluorescent dyes with absorption and emission wavelengths between 650 and 800 nm. Near-IR Cf dyes are significantly brighter and more stable than any other commercial dye of similar wavelengths. Near-IR Cf dyes offer important advantages over traditional visible light dyes. Because cellular or tissue components produce minimal autofluorescence in the near-IR region near-IR dyes have the potential to offer highly specific and sensitive detection in complex biological systems. Also because light with wavelength in the near-IR region has strong tissue penetration near-IR dyes are ideal for in vivo fluorescence imaging an emerging field that has advanced rapidly in recent years. futhermore near-IR dyes are also excellent dyes for in- or on-cell and membrane-based Western assays. Cf750 is so bright it can be excited at 633 nm but still emits stronger fluorescence at ~770 nm than APC-based tandem dyes making the dye particularly useful for flow cytometr