Thiol-PEG2-t-butyl ester is widely used in bioconjugation and chemical synthesis due to its unique properties. The thiol group allows for selective reactions with maleimides, gold surfaces, or other thiol-reactive groups, making it valuable for creating stable linkages in protein labeling, drug delivery systems, and surface modifications. The PEG (polyethylene glycol) spacer enhances solubility and reduces immunogenicity, which is particularly useful in biomedical applications such as therapeutic antibody development and nanoparticle functionalization. The t-butyl ester group provides protection for carboxylic acids during synthesis, enabling controlled deprotection in multi-step reactions. This compound is also employed in the preparation of peptide-based drugs and biomaterials, where precise conjugation and stability are critical. Its versatility makes it a key reagent in organic chemistry, materials science, and pharmaceutical research.