A 1-D coordination polymer catena [mu-fumaratobis (nicotinamide-kappa N)diaquacobalt (II)], (C16H18CoN4O8)(n), [Co(fum) (nia)(2)(H2O)(2)] or [CO(mu-C4H2O4) (C6H6N2O)(2)H2O)(2)](n) was synthesized and structurally characterized. The crystal structure is triclinic, space group P (1) over bar with parameters a = 7.2362 (8) angstrom, b = 7.5466 (8) angstrom, c = 9.0027 (10) angstrom, alpha = 109.582 (8)degrees, beta = 103.132 (9)degrees, gamma = 97.681 (9)degrees, V = 439.13 (9) angstrom(3), Z = 1. The asymmetric unit occurs from a Co-ll cation coordinated by the carboxylate 0 atom of the fumaric acid unit, N atom of the nicotinamide unit and together with one water molecule. In the title complex, Coll ion is octahedrally coordinated by two O atoms of the bridging fumarate dianion, two N atoms of nicotinamide molecules and two O atoms of water molecules. Theoretical calculations were obtained by using Density Functional Theory (DFT) methods. The vibrational frequencies and structural parameters were calculated by using DFT/B3LYP/6-311G** basis set in ground state. Molecular Electrostatic Potential (MEP) map and the frontier molecular orbitals (HOMO-LUMO) of the compound were created by using the optimized structures. The results of theoretical study using the OFT method at the B3LYP/6-311G** level are in good agreement with the experimental data. In the crystal, molecules are linked into a three-dimensional network by O-H center dot center dot center dot O and N-H center dot center dot center dot O hydrogen bonds. Hirshfeld surface analysis (d(norm) surfaces and two-dimensional fingerprint plots) for the title compound were performed and discussed. (C) 2018 Elsevier B.V. All rights reserved.