Assembling bimetallic (Ni-Ln)(3+) units and (W(CN)(8))(3-) in dmf yielded a series of trinuclear (3d-4f-5d} compounds resulting from the linkage of the {M(CN)(8)} to the Ni center. For all the derivatives ferromagnetic (Ni-W) and (Ni-Ln) (Ln = Gd, Tb, Dy, He, and Er) interactions are operative leading to high-spin ground states. The characteristic features for slow relaxation of the magnetization were found for trimetallic (NiTbW) but these are modulated by the solvent molecule composition.