ATTO 647N shows high thermal and photostability, high fluorescence quantum yield and excellent ozone resistance. Absorption and fluorescence are independent of pH, at least in the range of pH 2 to 11. The dye is moderately hydrophilic. ATTO 647N is a cationic dye. After coupling to a substrate the dye carries a net electrical charge of 1. Available modifications are: carboxylic acid, NHS-Ester, maleimide, amine, azide, iodoacetamide as well as conjugates with biotin, streptavidin or phalloidin.