The present invention is a platinum(II) compound comprising a beta-diketonate ligand represented by the following general formula: Or general formula: wherein R1 and R2 are independently selected from the group consisting of alkyl optionally substituted, heteroalkyl optionally substituted, and aryl optionally substituted; R3 and R4 are independently selected from the group consisting of ammonia, an optionally substituted heterocycle including at least one nitrogen, and an optionally substituted amine, or R3 and R4 can be joined together to form a bidentate ligand Z and Y are independently selected from the group consisting of O and S, provided at least one of Z and Y is S; and X— is a counterion. These compounds are useful in the treatment of cancer.