Azido-PEG2-Amine·Tos-OH is widely used in bioconjugation and click chemistry applications due to its azide functional group, which allows for efficient and selective reactions with alkynes via copper-catalyzed azide-alkyne cycloaddition (CuAAC). This compound is particularly valuable in the development of peptide and protein modifications, where it serves as a linker to introduce specific functionalities or to attach molecules of interest. Its PEG spacer enhances solubility and reduces steric hindrance, making it suitable for use in aqueous environments. Additionally, it is employed in the synthesis of drug delivery systems, where it facilitates the attachment of targeting moieties or therapeutic agents to carriers. The tosyl group further enables its use in nucleophilic substitution reactions, expanding its utility in organic synthesis and material science.