Thalidomide-PEG5-NH2 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, thereby enhancing the precision of drug delivery to specific cells or tissues. The thalidomide component is particularly valuable for its ability to bind to cereblon, a protein involved in the ubiquitin-proteasome system, which can be exploited to degrade disease-causing proteins. This makes it a key player in the development of treatments for cancers, autoimmune diseases, and other conditions where targeted protein degradation is beneficial. The PEG5 spacer improves solubility and reduces immunogenicity, while the NH2 group provides a reactive site for further chemical modifications, enabling the attachment of various functional groups or drugs.