Dicyanofumarate diesters have been discovered to be viable and versatile alternatives to tetracyanoethylene as building blocks for the synthesis of molecule-based magnets. The reaction of decamethylmanganocene, Mn(Cp*)2, and dimethyldicyanofumarate, DMeDCF, in methylene chloride at −50 °C gives a one-to-one charge-transfer salt ferromagnet, [Mn(Cp*)2][DMeDCF], that possesses one of the highest Curie temperatures, 10.6 ± 0.1 K, ever observed in this class of compounds. At 1.8 K, this compound exhibits hysteresis with H coer ∼ 7 kG. Measurement of ac susceptibility suggests some glassiness in the ferromagnetic state, similar to that seen for the tetracyanoethylene analogue, [Mn(Cp*)2][TCNE]. Diethyldicyanofumarate, DEtDCF, reacts with decamethylmanganocene to give the homologous salt, [Mn(Cp*)2][DEtDCF]. In contrast to the dimethyl ester, the magnetic properties of this compound are those of a glassy, hysteretic metamagnet that exhibits coercivity of around 10 kG at 1.8 K.