The syntheses and characterization of a series of binuclear iron(III) complexes of the ligands N,N′-bis(2- pyridylmethyl)ethane-1,2-diamine (bispicen), C 14H 18N 4, N,N′-bis(2-pyridylmethyl)propane-1,3-diamine (bispictn), C 15H 20N 4, and N,N′-bis(2-pyridylmethyl)- N,N′-bis(methyl)-1,2-ethanediamine, C 16H 22N 4, are described. The μ- oxo,μ-carbonatodiiron(III) complex {[(bispictn)Fe] 2(μ-O)(μ-CO 3)}(ClO 4) 2·3H 2O C 31H 46Cl 2Fe 2N 8O 15 ( 1) crystatlizes in space group P 1 of the triclinic system with two binuclear species in a cell of dimensions a=12.552(3), b=12.980(3), c=15.016(3) Å, α=88.49(3), β=68.57(3), γ=64.56(3)°. The tetradentate ligand binds the iron center in cis-β fashion. The structure has been refined to a final R factor of 0.0531 based on 2624 observed independent reflections. The complex contains a bent FeOFe unit with a bridging FeOFe angle of 129.7(3)° and associated average FeO and Fe···Fe separations of 1.803(7) and 3.264(2) Å, respectively. The FeO (carbonato) distances are 1.960(5) and 1.968(5) Å. The complex {[(bispicMe 2en)Fe] 2(μ-O)(μ-CO 3)}(ClO 4) 2·2H 2O, C 33H 48Cl 2Fe 2N 8O 14 ( 2) crystallizes in space group C2/ c of the monoclinic system with eight binuclear species in a cell of dimensions a=19.580(4), b=13.442(3), c=32.727(7) Å, β=94.07(3)°. The structure has been refined to a final R factor of 0.0634 based on 3279 observed independent reflections. The ligand binds the iron centers in cis-α fashion. The structure of the complex cation contains a bent FeOFe unit with a bridging FeOFe angle of 125.5(3)° and associated average FeO and Fe···Fe separations of 1.810(18) and 3.220(2) Å, respectively. The FeO (carbonato) distances are 1.930(6) and 1.925(7) Å. The novel μ-oxo,μ-sulfatodiiron(III) complex {[(bispicMe 2en)Fe] 2(μ-O)(μ-SO 4)}(ClO 4) 2·2H 2O, C 32H 48Cl 2Fe 2N 8O 15S ( 4) crystallizes in space group Pbca of the orthorhombic system with eight binuclear species in a cell of dimensions a=16.049(3), b=16.875(3), c=31.325(6) Å. The structure has been refined to a final R factor of 0.0682 based on 1776 observed independent reflections. The ligand binds the iron centers in cis-α fashion. The structure of the complex cation contains a bent FeOFe unit with a bridging FeOFe angle of 132.4(5)° and associated average FeO and Fe···Fe separations of 1.806(4) and 3.306(2) Å, respectively. The FeO (sulfato) distances are 1.980(11) and 1.981(11) Å. Cyclic voltammograms of the complexes reveal an irreversible reduction at c. −0.70 V versus Ag/AgCl reference electrode for 1, 3 and 4 and a quasi-reversible reduction for 2 at −0.585 V corresponding to the Fe 2(III/III) ↔ Fe 2(II/III) redox process.