Used as a bifunctional linker in bioconjugation chemistry, featuring an azide group at one end and a protected thiol (trityl sulfide) at the other. The azide group readily participates in copper-catalyzed azide-alkyne cycloaddition (CuAAC) click reactions, enabling efficient and selective coupling with alkyne-functionalized biomolecules such as proteins, peptides, or fluorescent probes. The thiol, upon deprotection of the trityl group, allows conjugation to maleimides or other thiol-reactive groups on biomolecules. The triethylene glycol-based spacer provides water solubility and flexibility, reducing steric hindrance and improving reaction efficiency. Its hydrophilic nature also helps maintain the solubility of conjugated compounds in aqueous environments, making it valuable in the development of bioconjugates for imaging, drug delivery, and diagnostic assays.