A dimeric Co(II) complex of ferron (=7-iodo-8-hydroxyquinoline-5-sulfonate) was isolated as crystals and structurally characterized. Weak (IH)-H-... and (IC)-C-... interactions involving the iodoquinoline rings and complementary steric requirements for (II)-I-... contacts led to self-assembly of the complex, which indicates versatile nature of the iodine atom in intermolecular interactions.