(meso-Tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphinato)manganese(III) tetracyanoethenide, [MnTP’P][TCNE], has been structurally and magnetically characterized. [MnTP’P][TCNE] (C96H108MnN8O4) belongs to the triclinic (No. 2) space group with a = 8.597(2) Angstrom, b = 14.756(4) Angstrom, c = 17.573(5) Angstrom, alpha = 101.16(2)degrees, beta = 100.56(2)degrees, gamma = 96.37(2)degrees, and Z = 1. Due to the oxidative instability of the phenoxy groups, [(MnTP)-T-III’P][TCNE] was prepared from the reaction of [(MnTP)-T-III’P]OAc with the strong acid H(2)TCNE (pK(a) = 3.6) in the presence of TCNE to form acetic acid and the product. [MnTP’P][TCNE] is a coordination polymer with the Mn(III) sites bridged by trans-mu 2-bound [TCNE](.-) with relatively short (8.587 Angstrom) intrachain and long (greater than or equal to 14.756 Angstrom) interchain Mn Mn separations. The magnetic data above 210 K obey the Curie-Weiss expression with an effective Theta value of 90.0 K, the largest yet reported for a soluble molecule-based magnet. In addition to a 15 K T-c hysteretic behavior with a coercive field of 100 Oe is observed at 5 K. Despite the significant steric bulk leading to the substantially decreased interchain interactions that are crucial for magnetic ordering, the T-c is unexpectedly high and suggests that other linear chain systems may be expected to exhibit magnetic ordering at higher temperatures.