Thalidomide-O-amido-PEG4-azide is primarily utilized in the field of targeted drug delivery and proteolysis-targeting chimeras (PROTACs). Its structure allows it to act as a linker molecule, connecting therapeutic agents to targeting moieties. The azide group enables click chemistry reactions, facilitating the attachment of various biomolecules or drugs. This chemical is particularly valuable in cancer research, where it helps design compounds that selectively degrade disease-causing proteins. Additionally, its PEG4 spacer enhances solubility and reduces steric hindrance, improving the efficiency of drug delivery systems. It is also employed in the development of bioconjugates for studying protein interactions and cellular pathways.