We have prepared a series of 94.5%-enriched Fe-57(II) complexes of tetramesitylporphyrin and octaethylporphyrin having various bis- or mixed axial ligation and investigated them by both NMR and Mossbauer spectroscopy. The results obtained, and literature values for MbCO and cytochrome c, show a rough correlation between Delta E(Q) and delta(Fe). This correlation suggested that the previously-reported chemical shifts of the complexes [TPPFeL(2)], L = pyridine-d(5), and pyrrolidine (Nozawa, T.; Sate, M.; Hatano, M.; Kobayashi, N.; Osa, T. Chem. Lett. 1983, 1289) might be incorrect; we have thus used the rapid pulsing method of Schwenck to detect the signal of the bis-pyridine-d(5) complex at 11 715 ppm, within its predicted chemical shift range, based upon the delta(Fe) vs Delta E(Q) correlation, and similar to 4,400 ppm to lower shielding than originally reported. These findings emphasize the value of the Mossbauer-NMR correlation in aiding the detection of Fe-57 NMR signals, as well as the perils of seeking these easily "folded" signals without such a correlation.