(Z)-SMI-4a, chemically named (5Z)-5-[3-(trifluoromethyl)benzylidene]-1,3-thiazolidine-2,4-dione, is a synthetic small-molecule inhibitor primarily known for targeting 3-phosphoinositide-dependent protein kinase-1 (PDK1), a key regulator in the PI3K/Akt signaling pathway that is often dysregulated in cancer.