The title compound, cobalt 4',7-diethoxylisoflavone-3'-sulfonate([Co(H2O)(6)](X)(2)center dot 8H(2)O, X = C19H17O4SO3) was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in the triclinic space group P-1 with cell parameters a = 9.026(3) angstrom, b = 16.431(5) angstrom, c = 18.195(6) angstrom, alpha = 72.289(4)degrees, beta = 87.498(4)degrees, gamma = 82.775(5)degrees, V = 2550.1(13)angstrom(-3), D-c = 1.419 Mg m(-3), and Z = 2. The results show that the title compound consists of one cobalt cation, six coordinated water molecules, eight lattice water molecules, and two 4',7-diethoxylisoflavone-3'-sulfonate anions, C19H17O4SO3-. Two anions have different conformations. Twelve H atoms of six coordinated water molecules, as donors, form hydrogen bonds with four oxygen atoms of sulfo-groups of two anions and eight oxygen atoms of eight lattice water molecules. In addition, pi(...)pi stacking interactions exist in the crystal structure, which together with hydrogen bonds lead to supramolecular formation with a three-dimensional network.