Pro-chelator compositions featuring disulfide masks that upon activation yield active chelators. The pro-chelator compositions may be activated intracellularly, for example within cells featuring metal ion dysregulation, cells that proliferate abnormally, etc. The pro-chelators of the present invention include thiosemicarbazones, semicarbazones, and aroyl hydrazones. The pro-chelator compositions of the present invention may be used for a variety of purposes including inhibiting cell proliferation, or treating conditions associated with metal ion dysregulation or abnormal cell proliferation.