Bis-PEG1-acid is widely used in bioconjugation and pharmaceutical formulation due to its ability to link molecules through reactive functional groups. Its bifunctional structure allows for the cross-linking of peptides, proteins, or small molecules, making it valuable in the development of drug delivery systems and PEGylation strategies. It enhances solubility and stability of conjugated compounds while reducing immunogenicity. It is also employed in creating hydrogels and functionalized polymers for use in biomedical applications such as tissue engineering and controlled release formulations. The short PEG spacer provides moderate flexibility and hydrophilicity, suitable for applications requiring minimal steric interference.