A series of 10 novel polyoxometalate (W/Mo) compounds connected via a trivalent lanthanide cation bridge, H-2{[K(H2O)(2)](2)[Ln(H2O)(5)](2)(H2M12O42)}(.)nH(2)O (Ln = La, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu; M = W or W/Mo) (1 - 10), were designed and synthesized on the basis of the abduction of Al3+ in aqueous solution. X-ray diffraction analyses reveal that the structures of complexes 1 -10 are three-dimensional frameworks assembled from the arrangement of H2M12O4210- (named paradodecmetalate-B) and Ln(H2O)(5)(3+) with two planes, which are constructed via the unification of H2M12O4210- and Ln(H2O)(5)(3+), along the [100] and [001] directions. Magnetic measurements reveal the paramagnetic properties and a strong ferromagnetic coupling between the two nearest-neighboring lanthanide cations, Ln(3+) (Ln = Dy, Er), within the circle for compounds 2 and 4-9.