Thalidomide-O-PEG4-Boc is primarily utilized in the field of medicinal chemistry and drug development. Its application is significant in the design and synthesis of PROTACs (Proteolysis Targeting Chimeras), which are innovative therapeutic agents aimed at degrading specific disease-causing proteins. The compound serves as a crucial linker component, connecting the target protein-binding moiety to the E3 ubiquitin ligase-recruiting moiety. This linkage is essential for the targeted protein degradation process, enabling the selective removal of proteins implicated in various diseases, including cancer and neurodegenerative disorders. Additionally, Thalidomide-O-PEG4-Boc is employed in the development of novel small molecules for research purposes, aiding in the exploration of new therapeutic pathways and mechanisms. Its role in facilitating the creation of bifunctional molecules underscores its importance in advancing precision medicine and targeted therapies.