We report a pair of fluorinated, redox-active copper complexes for potential use as F-19 MRI contrast agents for detecting cellular hypoxia. Trifluorinated Cu(II) ATSM-F-3 displays the appropriate redox potential for selective accumulation in hypoxic cells and a completely quenched F-19 NMR signal that is "turned on" following reduction to Cu(I). Incubation of cancer cells with CuATSM-F-3 resulted in a selective detection of F-19 signal in cells grown under hypoxic conditions.