Estrogen receptor modulator 10 (compound G-5b) is an estrogen receptor (ER) antagonist ( IC 50 =6.7 nM) and degrader ( DC 50 =0.4 nM). Estrogen receptor modulator 10 is developed based on the Fulvestrant molecule and can rapidly degrade ER receptors through the proteasome pathway. Estrogen receptor modulator 10 can induce cell apoptosis and block cells in the G1/G0 phase and can be used in cancer research.