Used in the development of targeted protein degradation therapies, particularly in PROTAC (Proteolysis Targeting Chimeras) design. The thalidomide moiety binds to the E3 ubiquitin ligase complex, enabling ubiquitination and subsequent degradation of target proteins. The PEG4 linker provides water solubility and flexibility, improving pharmacokinetic properties and reducing aggregation. The terminal carboxylic acid group allows for conjugation to targeting ligands or small molecules through standard coupling chemistry. This compound is valuable in creating bifunctional degraders that bridge disease-related proteins to the cellular degradation machinery, offering potential in cancer therapy and other diseases involving pathological or undruggable proteins.