A　novel　inorganic-organic　hybrid　polyoxotungstate　H4[Ni(en)2]2[Ni(en)(dap)]2[Ni(dap)2]2[Ni4(en2)(PW9O34)2]-{[Ni(H2O)5]2[Ni4(en)2(PW9O34)2]}·12H2O　(1,　en　=　ethylenediamine,　dap　=　1,2-diaminopropane)　has　been　successfully　synthesized　under　hydrothermal　conditions　and　structurally　characterized　by　single-crystal　X-ray　diffraction,　powder　X-ray　diffraction,　infrared　spectroscopy,　elemental　analysis　and　thermogravimetric　analysis,　respectively.　Single-crystal　structure　analysis　reveals　that　1　exhibits　a　2-D　network　structure　based　on　two　kinds　of　tetra-Ni-substituted　sandwich-type　Keggin　polyoxoanions　linked　by　different　types　of　Ni-organoamine　complexes.　©　2016　Elsevier　B.V.