Used as a key intermediate in the synthesis of peptide-based pharmaceuticals and bioconjugates due to its bifunctional structure containing both carboxylic acid and thiol-reactive amide groups. The molecule enables controlled linker formation between biomolecules and functional payloads, such as drugs, dyes, or detection tags, especially in targeted therapies and diagnostic reagents. Its hydrophilic ethoxy spacers enhance solubility in aqueous systems, making it suitable for bioconjugation under physiological conditions. Also applied in the development of PEG-like linkers with improved metabolic stability and reduced immunogenicity.