The reaction of mercury(II) chloride with 5-amino-2,4,6-triiodo-isophthalic acid in pyridine solution leads to the formation of the title compound, [Hg(C(8)H(2)I(3)NO(4))(C(5)H(5)N)(2)](n). The structure contains a four-coordinate Hg(2+) ion in a distorted tetra-hedral geometry, which lies on a crystallographic twofold axis. The Hg(2+) ion is bonded to two N atoms from two pyridine ligands and two carboxylate O atoms from two 5-amino-2,4,6-triiodo-isophthalate anions. The two carboxyl-ate groups of individual 5-amino-2,4,6-triiodo-isophthalate anions act as a bridge to the Hg centers. This anion also resides on a twofold axis, which passes through the amino N and the trans standing I atoms. The Hg-O distance is 2.337 (6) and the Hg-N distance is 2.244 (8) Å.