Three metal–organic polymeric networks, Ni(C 8 H 6 NO 2 ) 2 (H 2 O) 2 (1), Co(C 8 H 6 NO 2 ) 2 (2), and Cu(C 8 H 6 NO 2 ) 2 (H 2 O) 2 (3), were synthesized by the hydrothermal method. Single-crystal X-ray analysis revealed that within these compounds metal centers are linked through trans-4-pyridylacrylate ligands to form interpenetrating infinite networks. The Ni(II) and Cu(II) compounds possess an overlay of interpenetrating square grid layers, whereas the Co(II) compound possesses interpenetrating diamondoid networks. Comparing these three compounds, the formation of cavities potentially for guest molecule inclusion within the interpenetrating networks could be achieved by taking advantage of the coordination nature of metals. Crystal structures of all three compounds were determined by single-crystal X-ray diffraction methods and solved by direct method. Crystal data for 1: orthorhombic, space group Pbcn, a=13.735(3) Å, b=6.995(2) Å, c=16.723(3) Å, V=1606.7(6) Å 3 , Z=4, final refinement (I>2σ(I)): R1=0.0296, wR2=0.0843. Crystal data for 2: monoclinic, space group Cc, a=11.5717(9) Å, b=21.2838(16) Å, c=8.5504(7) Å, β=130.5210(10)°, V=1600.8(2) Å 3 , Z=4, final refinement (I>2σ(I)): R1=0.0347, wR2=0.0879. Crystal data for 3: orthorhombic, space group Pbcn, a=13.6844(13) Å, b=7.5053(8) Å, c=15.929(4) Å, V=1636.0(5) Å 3 , Z=4, final refinement (I>2σ(I)), R1=0.0299, wR2=0.0787.