CY7-SE triethylamine is a type of CY dye. CY stands for cyanine, which is a compound formed by two nitrogen atoms linked by an odd number of methine units. Cyanine compounds are known for their long wavelengths, adjustable absorption and emission, high extinction coefficients, good water solubility, and relatively simple synthesis. CY series dyes are commonly used for labeling proteins, antibodies, and small molecule compounds. For protein and antibody labeling, they can be conjugated through straightforward mixing reactions. Below, we detail a method for labeling proteins and antibodies, which can serve as a useful reference.