Sulfo-Cy7.5 carboxylic acid is a dye derivative of Cyanine 7.5 (Cy7.5) (HY-D0926) with carboxylic acid and sulfonate ion (sulfonate) functional groups. The sulfonate ion increases the water solubility of the compound, making it suitable for use in aqueous solutions. Cy7.5 is a near-infrared fluorescent dye commonly used in biomedical research areas such as biomarkers and cell imaging. Sulfo-Cy7.5 carboxylic acid can be covalently bound to some biomolecules (especially antibodies, proteins, etc.) to track their location and dynamic changes in biological samples.