Thalidomide-O-amido-CH2-PEG3-CH2-NH-Boc is a synthesized conjugate that functions as an E3 ligase ligand-linker. It includes the cereblon ligand derived from Thalidomide and a linker. This compound, Thalidomide-O-amido-CH2-PEG3-CH2-NH-Boc, is employed in the synthesis of PROTAC BET degraders.