Bis(2,2':5',2'-terpyrid-4'-yl) diethylene glycol was synthesized as a monomer unit and further utilized for polymerization with FeCl2 in order to form water-soluble coordination polymers. Viscosity measurements and film-forming properties indicate the formation of linear coordination polymers or larger ring structures. The terpyridine/iron(II) complexes are stable up to temperatures of 210degreesC, but can be uncomplexed by the addition of an excess of a strong competitive ligand (HEDTA) under mild conditions.