Highly crystalline films of a silver-based coordination polymer, [Ag-5(C6S6)](n) (Ag-BHT, BHT = benzenehexathiol), have been prepared. The structure of Ag-BHT, solved by combining rotation electron diffraction and powder X-ray diffraction techniques, indicates that it has a lamellar structure with alternatively stacked two-dimensional Ag-S networks and layers composed of one-dimensional metal-dithiolene polymers. In addition, the polycrystalline Ag-BHT film shows high electrical conductivity of up to 250 S.cm(-1) at 300 K. The ultraviolet-photoelectron spectroscopy and electronic band structure calculations reveal that this can be attributed to the partially filled valence band and the unique two-dimensional Ag-S networks.