Based on the binding mode of our previously discovered dual inhibitor of Bcl-2 and Mcl-1, 3- thiomorpholin-8-oxo-8H-acenaphtho [1, 2-b] pyrrole-9-carbonitrile (3, S1), a library of 9- substituted 3 derivatives was synthesized to further probe the p4 pocket of the two targets. By NMR, structure–activity relationship study, and site-directed mutation, compound 6d (3-(4- aminophenylthio)-8-oxo-8H-acenaphtho [1, 2-b] pyrrole-9-3-phenyl) propylamine) was ...