In the title coordination polymer, [Hg2Cl4(C26H20N6)] n, one Hg-II ion is coordinated by four N atoms from the benzylbis((pyridin-2-yl) methylidenehydrazone) ligand and two Cl- ions in a very distorted cis-HgCl2N4 octahedral geometry. The other Hg-II ion is coordinated in a distorted tetrahedral geometry by four Cl- ions. Bridging chloride ions link the HgII ions into a chain propagating in : the Hg-Cl bridging bonds are significantly longer than the terminal bonds. The dihedral angle between the central benzene rings of the ligand is 83.3 (2)degrees. The packing is consolidated by weak C-H ... Cl hydrogen bonds and C-H ...pi interactions.