Class I phosphoinositide 3-kinases (PI3Ks), in particular PI3Kγ, have become attractive drug targets for inflammatory and autoimmune diseases. Here, we disclose a novel series of furan- 2-ylmethylene thiazolidinediones as selective, ATP-competitive PI3Kγ inhibitors. Structure- based design and X-ray crystallography of complexes formed by inhibitors bound to PI3Kγ identified key pharmacophore features for potency and selectivity. An acidic NH group on ...