The structures and magnetic properties of two products that result from the reactions of [Mn(TPA)(CH3CN)(2)](CIO4)(2), TPA = tris(2-pyridylmethyl)amine and potassium tetracyanoethylenicle, KTCNE, are reported. [Mn(TPA)(TCNE)](2)[mu(2)-(TCNE)(2)] (1) and [Mn(TPA)(mu(4)-C-4(CN)(8))(0.5)]center dot CIO4 (2) are obtained by using two different ratios of the initial reactants. Each was intended to possess two or more cis-TCNE radical anions (TCNE center dot/-) as ligands. 1 is a dinuclear species that crystallizes in the triclinic system in the space group P(1) over bar, with a = 10.4432(17), b = 12.2726(16), and c = 13.708(2) angstrom; alpha = 88.505(12), beta = 75.560(14), and gamma = 87.077(12)degrees; V = 1698.9(4) angstrom(3); and Z = 1 and features two metal centers each with three nearly orthogonal TCNE center dot/- ligands. However, the three TCNE center dot/- ligands are all dimerized via the formation of four-center, two-electron bonds: two bridge-the two Mn(II) centers, and a third TCNE center dot/- ligand forms an intermolecular bond to another equivalent TCNE center dot/-. 2 crystallizes in the tetragonal system in the space group P4(2)2(1)2, with a = 17.170(3), b = 17.170(3), and c = 17.1837(6) angstrom; V = 5065.9(13) angstrom(3); and Z = 8. It consists of a ribbon-like coordination polymer containing the previously observed but still relatively rare octacyanobutyl dianion. The [C-4(CN)(8)](2-) anion is derived from the dimerization of two TCNE radical anions via the formation of anew sigma bond, and each anion bridges four Mn(II) centers. Both 1 and 2 display magnetic behavior consistent with only weak antiferromagnetic coupling between the high-spin d(5) Mn(II) in which the TCNE center dot/- are rendered diamagnetic through dimerization.