BH3-interacting domain (Bid) is cleaved by caspase-8 to produce the truncated protein tBid, which facilitates cytochrome c release from mitochondria and drives apoptosis. BI-6C9 is an inhibitor of tBid (Kd = 20 µM), blocking the release of both cytochrome c and second mitochondria-derived activator of caspase from mitochondria. It prevents apoptosis in neurons treated with glutamate or oxygen-glucose deprivation. BI-6C9 (10 µM) also inhibits the nuclear translocation of apoptosis-inducing factor AIF, preventing the death of ovarian OVCAR-3 cancer cells induced by IFN-α2a.