Four “mixed” bis(thiosemicarbazone) derivatives of pyruvaldehyde were synthesized that incorporate two dissimilar thiosemicarbazone functions. The corresponding [ 67 Cu]copper(II) complexes were prepared and evaluated as possible copper radiopharmaceuticals. The pyruvaldehyde-based mixed bis(thiosemicarbazone) ligands, CH 3 C[=NNHC(S)NHMe]CH[=NNHC(S)NHEt] (1), CH 3 C[=NNHC(S)NHMe]CH[=NNHC(S)NEt 2 ] (2), CH 3 C[=NNHC(S)NHMe]CH[=NNHC(S)-cyclo-N(CH 2 ) 5 ] (3), and CH 3 C[=NNHC(S)NHMe]CH[=NNHC(S)-cyclo-N(CH 2 ) 6 ] (4), were obtained by reaction of the appropriate thiosemicarbazide derivative with pyruvaldehyde-2-N 4 -methylthiosemicarbazone (CH 3 C[=NNHC(S)NHMe]CHO). The 67 Cu-labeled copper(II) complexes of ligands 1-4 were prepared and screened in a rat model to assess the potential of each chelate as a 62 Cu-radiopharmaceutical for imaging with positron emission tomography. The 67 Cu-complexes of ligands 1–4 exhibit significant uptake into the brain and heart 1 min following intravenous administration to rats. For the 67 Cu-complexes of ligands 2, 3, and 4, the cerebral and myocardial uptake of 67 Cu is two-to-threefold lower at 2 h than at 1 min postinjection, due to significant biological clearance of these 67 Cu-chelates. However, the 67 Cu-complex of 1 affords cerebral and myocardial uptake and retention comparable to that of [ 67 Cu]Cu-PTSM in this model. Although the kinetics of this new agent appear attractive, ultrafiltration studies using solutions of dog and human serum albumin reveal that the 67 Cu-complex of ligand 1, like Cu-PTSM, interacts more strongly with human albumin than dog albumin. Thus, this new agent would appear to offer no advantage over Cu-PTSM as a 62 Cu-labeled tracer for evaluation of regional tissue perfusion.