Used in bioconjugation and molecular labeling due to its ability to link biotin with thiol-reactive groups. The dithiolane ring enables covalent attachment to sulfhydryl groups on proteins or peptides, while the biotin moiety allows strong binding to streptavidin or avidin for detection, purification, or immobilization in assays like ELISA, Western blotting, and flow cytometry. The extended ethylene glycol spacer reduces steric hindrance, improving binding efficiency and accessibility in complex biological systems. Commonly applied in developing diagnostic kits, targeted drug delivery systems, and surface functionalization of biosensors.