A giant barocaloric effect (BCE) in a molecular material Fe3(bntrz)6(tcnset)6 (FBT) is reported, where bntrz = 4-(benzyl)-1,2,4-triazole and tcnset 1,1,3,3-tetracyano-2-thioethylepropenide. The crystal structure of FBT contains trinuclear transition metal complex that undergoes an abrupt spin-state switching between the state which all three FeII centers are high-spin (S 2) electronic configura...