A novel one-dimensional chainlike organic-inorganic polymer [Cu(en)(2)](3)[Cu(en)(2)(H2O)](2){[Cu-4(GeW9O34)(2)][Cu(en)(2)]}center dot 9.5H(2)O (en = ethylenediamine) has been synthesized by hydrothermal reaction in good yield, and characterized by elemental analysis, IR, TG-DTA, EPR, magnetic properties, and single-crystal X-ray diffraction. The diffraction analysis reveals that the polymer represents the first high-dimensional organic-inorganic hybrid based on the sandwich-type polyoxometalates linked by transition-metal coordination cations.