In the title coordination polymer, [Fe(C 8 H 6 N 5 O 4 ) 2 ] n {or [Fe L 2 ] n ,where H L = 2-[(1 H -1,2,4-triazol-1-yl) meth­yl]-1 H -imidazole-4,5-dicarb­oxy­lic acid)}, the Fe II ion, located on an inversion centre, is six-coordinated by two O atoms and four N atoms from two L − ligands in a distorted octa­hedral geometry [Fe—O = 2.1452 (13), Fe—N = 2.1316 (14) and 2.2484 (15) Å]. There is an intra­molecular O—H⋯O hydrogen bond in each L − ligand. Being an effective tridentate bridging ligand, the deprotonated L − anions link two Fe II atoms, yielding a chain-like polymer propagating along [100]. In the crystal, these polymer chains are linked via N—H⋯N hydrogen bonds, forming a two-dimensional network.