Mcl-1 inhibitor 10 (compound 43) is a relatively strong MCL-1 inhibitor ( IC 50 =0.67 μM). Mcl-1 inhibitor 10 interacts with specific binding sites of MCL-1 protein to block the pro-survival signal of MCL-1 and push cancer cells into apoptosis. Mcl-1 inhibitor 10 can be used in the study of MCL-1 dependent cancers.