The invention provides compositions, e.g., small molecules, that disrupt the activity of protein kinases, including constitutively activated protein kinases, such as kinases constitutively activated through mutations, and kinases in their native inactivated state, and methods for making and using them. In one aspect, compositions of the invention bind a protein kinase in its inactive conformation involving the conserved asparagine-phenylalanine-glycine residue motif, or “Asp-Phe-Gly” or “DFG” motif, of the activation loop in the allosteric binding site. The small molecule protein kinase inhibitors of the invention comprise or are derivatives or analogs of oxadiazoles, thiadiazoles, oxazoles, thiazoles, arylamides, quinolones, pyrazoles, pyrazolones, imides, pyrolles, imidazoles and/or triazoles.