This invention provides for compounds, compositions, and methods that involve anti-proliferative and anti-neoplastic activity in cancer cells. In particular, a series of benzimidazole, purine, imidazopyridine, and imidazopyrizine compounds having selected substitution patterns are disclosed, and the activity of various subject compounds is demonstrated. For example, the invention provides compounds having the general formula: their pharmaceutical compositions, and methods of treatment using the subject compounds and compositions.