The construction, crystal structure and properties and potential application of metal imidazoledicarboxylate frameworks have currently attracted considerable attention. A novel open-framework Lanthanide imidazoledicarboxylate, [Tb (HpyimdC)(C2O4)0.5(H2O)]·(H2O)3 (compound 1), was constructed from 2-(pyridine-3-yl)-1H-4,5-imidazoledicarboxylate (H3PyImdc) and Oxalate coordinated with lanthanide under solvothermal conditions. Single-crystal X-ray diffraction analysis reveals that compound 1 crystallized in the monoclinic space group C2/c (No. 15). Oxalate chelated with Tb to form a one-dimensional zigzag chain, H3pyimdc with selective nitrogen−oxygen chelating site, constructed these chains into metal organic frameworks featuring extra-large channels deposited by guest molecules. Further characterizations for compound 1 have been performed, including X-ray powder diffraction, IR Spectrum and elemental analysis. Synthesis, crystal structure and structural characterizations for 1 were reported in this paper.