Azido-PEG6-CH2COOH is widely used in bioconjugation and chemical biology due to its azide functional group and PEG spacer. It serves as a linker for attaching biomolecules, such as proteins, peptides, or antibodies, to other molecules or surfaces via click chemistry, particularly copper-catalyzed azide-alkyne cycloaddition (CuAAC). The PEG6 spacer enhances solubility and reduces steric hindrance, making it ideal for creating stable conjugates in drug delivery systems, diagnostic probes, and targeted therapies. Its carboxylic acid group allows further functionalization or coupling to amine-containing molecules, expanding its utility in developing bioconjugates for research and therapeutic applications.