Used as an active ester in bioconjugation chemistry, particularly for the modification of proteins, peptides, or other biomolecules containing primary amines. Its long polyunsaturated fatty acid chain provides hydrophobic character and potential for membrane interaction, while the activated ester group enables efficient amide bond formation under mild conditions. Commonly employed in the development of antibody-drug conjugates (ADCs), targeted therapeutics, and functionalized lipids for drug delivery systems. Also utilized in metabolic labeling and lipid-protein interaction studies due to the structural similarity of the docosahexaenoate moiety to natural omega-3 fatty acids. Stable in anhydrous environments and compatible with a range of coupling reactions in organic and aqueous-organic solvents.