This invention relates to novel substituted styryl benzylsulfones that are multikinase inhibitors and pharmaceutically acceptable acid addition salts thereof. The invention also provides compositions comprising a compound of this invention and the use of such compositions in methods of treating diseases and conditions beneficially treated by an agent that inhibits kinases, such as phosphatidylinositol 3-kinase (PI3-K) and polo-like kinase (PLK-1).