Cy5.5, SE is widely used in biomedical research for labeling biomolecules such as proteins, peptides, and nucleic acids. Its near-infrared fluorescence makes it ideal for in vivo imaging, allowing researchers to track biological processes in real time with minimal background interference. It is particularly valuable in cancer research for tumor detection and monitoring therapeutic responses. Additionally, it is employed in molecular diagnostics for sensitive detection of target analytes in assays. The dye’s stability and high quantum yield ensure reliable and efficient imaging in both preclinical and clinical studies.