– BMS-1166-N-piperidine-CO-N-piperazine dihydrochloride, a resorcinol di-Ph ether scaffold-based programmed cell death-1 (PD-1)/programmed cell death ligand 1 (PD-L1) inhibitor, inhibits the PD-1/PD-L1 interaction with an IC50 of 39.2 nM. It contains the target protein PD-1/PD-L1 ligand and PROTAC linker, which can be used to synthesize PROTAC PD-1/PD-L1 degrader-1 and has anticancer activity. Additionally, it serves as a diluent for the preparation of tablets for direct compression.