A　new　2-D　Cu(II)　coordination　polymer,　[Cu-2(L)(H2O)(3)]4.5H(2)O　(1)　[H4L=5,5-(pyrazine-2,3-diylbis(azanediyl))diisophthalic　acid],　has　been　synthesized　from　the　reaction　of　Cu(NO3)(2)3H(2)O　with　H4L　under　solvothermal　conditions.　H4L　was　prepared　and　characterized　by　H-1　NMR,　C-13　NMR,　elemental　analysis　(EA),　and　infrared　spectroscopy　(IR).　X-ray　single-crystal　diffraction　analysis　reveals　that　1　crystallized　in　the　hexagonal　space　group　P6(5)22　with　a=16.318(1),　b=16.318(1),　c=35.632(6)angstrom,　V=8217.0(8)angstrom(3),　Z=12　and　afforded　2-D　grid-like　double　layers　with　a　[3,5]　topology　network.　The　staggered　arrangement　of　the　2-D　layers　afforded　a　dense　structure　through　H-bonds.　Further　characterizations　for　1　were　performed　by　powder　X-ray　diffraction,　thermogravimetric　analysis,　EA,　IR,　etc.　Magnetic　measurements　revealed　antiferromagnetic　interactions　between　the　adjacent　Cu(II)　centers　within　1.　[GRAPHICS]　.