This bifunctional compound serves as a linker in the synthesis of proteolysis targeting chimeras (PROTACs) and other targeted protein degradation agents. It features an N-hydroxysuccinimide (NHS) active ester for conjugation to ligands targeting proteins of interest, linked via a short polyethylene glycol (PEG) chain containing a hydrolyzable ester bond to a pomalidomide-derived moiety with a glutarimide group. This glutarimide enables specific recruitment of the E3 ubiquitin ligase cereblon, facilitating ubiquitination and proteasomal degradation of target proteins. The ethylene glycol units improve aqueous solubility, while the ester bond allows for controlled linker cleavage under physiological conditions. It is particularly valuable in oncology for developing therapies against challenging targets, such as transcription factors or scaffolding proteins, that are difficult to inhibit with traditional small molecules.