Cyanide-bridged bimetallic assemblies, [Ni(dmen)(2)](2)[Fe(CN)(6)]X.nH(2)O (dmen = 1,1-dimethylethylenediamine; X- = p-phenylbenzenesulfonate (PhBSO3.), n = 5, (1); p-tolylsulfonate (TolSO(3)(.)), n = 6, (2)), have been prepared. The X-ray crystallography for the assemblies has revealed a 2-D network structure based on Fe4Ni4 square units extended by Fe-CN-Ni linkage, They show a long-range ferromagnetic ordering around 10 K based on a ferromagnetic interaction between the adjacent Fe(Ill) and Ni(II) ions through cyanide bridge. And dehydrated compounds of 1 and 2 also show a long-range ferromagnetic ordering.