Tamoxifen-PEG-Clozapine is an estrogen receptor α ( ERα ) PROTAC degrader. Tamoxifen-PEG-Clozapine degrades ERα via a ubiquitin-proteasome system that uses the ubiquitin protein ligase E3 component N-recognin 5. Tamoxifen-PEG-Clozapine can be used for the research of cancer. (Pink: ERα inhibitor ; Black: linker ; Blue: CRBN Ligand )