This paper reports the first detailed electrochemistry of iron(III) mu-oxo porphycene dimers. The investigated compounds are represented as [(Pc)Fe]O-2 where Pc = the dianion of octaethylporphycene (OEPc), etioporphycene (EtioPc), tetrapropylporphycene (TPrPc) or tetra-tert-butylporphycene (TBuPc). Each derivative undergoes four reversible one-electron reductions and four reversible one-electron oxidations, and this data is compared to that of the related iron(III) porphyrin mu-oxo dimers which in non-aqueous media may undergo up to four one-electron oxidations but only a single reversible one-electron reduction. The site of electroreduction during the first two one-electron transfers of [(Pc)Fe]O-2 was evaluated utilizing thin-layer UV-visible spectroelectrochemistry and indicated the stepwise addition of two electrons to the conjugated pi-ring system of the porphycene rather than to the Fe(III) metal ions of the mu-oxo dimer. Comparisons are made between the electrochemistry and UV-visible spectra of electroreduced [(EtioPc)Fe]O-2 and a related mu-oxo porphycene dimer possessing the same macrocycle but electroinactive metal ions, [(EtioPc)Al]O-2, as well as between dimeric [(OEPc)Fe]O-2 and monomeric (OEPc)FeCl. This data is self-consistent and clearly indicates that the first two reductions of [(Pc)Fe]O-2 occur at the porphycene macrocycle rather than at the Fe(III) center as has been suggested for iron Il-oxo porphyrin dimers. The difference in reductive electrochemistry between [(Pc)Fe]O-2 and [(P)Fe]O-2 (where P = the dianion of a porphyrin ring) is interpreted in terms of different sites of electron transfer and a lowering of the LUMO energy level.