Used in pharmaceutical research as a linker or intermediate in the development of targeted protein degraders, particularly in PROTAC (proteolysis-targeting chimeras) technology. Its structure enables conjugation between a target-binding ligand and an E3 ubiquitin ligase recruiter, facilitating the degradation of disease-related proteins. The polyethylene glycol (PEG) chain enhances solubility and flexibility, improving pharmacokinetic properties. Commonly applied in oncology and immunomodulatory drug development due to its role in compounds related to thalidomide derivatives, which engage the cereblon E3 ligase complex.