A novel 3D polymer 1 (C26H22CoN4O4, M-r = 513.41) constructed from H(2)C(4)BIm (2,2'-(1,4-butanediyl)bis(1H-benzimidazole)], 1,3-bdc (1,3-benzenedicarboxylate) and Co(II) has been successfully synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction analysis. The crystal belongs to the tetragonal system, space group I-42d with a = 24.315(5), b = 24.315(5), c = 8.343(2) angstrom, V = 4933(2) angstrom(3), Z = 8, D-c = 1.383 g/cm(3), mu(MoK alpha) = 0.735 mm(-1), F(000) = 2120, S = 1.156, the final R = 0.0596 and wR = 0.1346 for 1529 reflections with I > 2 sigma(I). Complex 1 contains 1D chains which are connected by extensive hydrogen-bonding interactions to form the 2D folded layer and 3D framework, which also stabilize the structure.