Used in bioconjugation and labeling applications, particularly in the development of fluorescent probes for imaging and diagnostics. It is commonly employed in fluorescence microscopy, flow cytometry, and in vivo imaging due to its Cy5 fluorophore, which provides strong near-infrared emission. The PEG3 spacer enhances solubility and reduces steric hindrance, making it suitable for attaching to biomolecules like proteins, peptides, or antibodies without disrupting their function. This compound is valuable in studying cellular processes, tracking molecular interactions, and designing targeted therapeutics.