Used extensively in bioconjugation and labeling applications, it serves as a versatile linker for attaching fluorescent probes to biomolecules. Its DBCO group enables click chemistry reactions, particularly with azide-containing compounds, facilitating efficient and selective conjugation. The PEG4 spacers enhance solubility and reduce steric hindrance, making it ideal for labeling proteins, peptides, or antibodies in live-cell imaging and flow cytometry. The Cy5 fluorophore provides strong near-infrared fluorescence, enabling deep-tissue imaging and high-sensitivity detection in biological studies. Its design is particularly useful in developing targeted imaging agents and therapeutic conjugates for research and diagnostics.