Six tartrate-bridging rare-earth-substituted polytungstoarsenates [RE2(C4H4O6)(C4H2O6)(As W9O33)]2(18-) (Ho(III) (1), Er(III) (2), Tm(III) (3), Yb(III) (4), Lu(III) (5), and Y(III) (6)) have been synthesized under conventional solution conditions. They have been further characterized by elemental analyses, X-ray powder diffraction (XRPD), IR and UV-vis spectroscopy and single-crystal X-ray diffraction. Preliminary variable-temperature magnetic susceptibility measurements indicate that 1-4 exhibit antiferromagnetic coupling.