In the present work di-urethane cross-linked poly(oxyethylene) (POE)/siloxane hybrids (di-urethanesils) incorporating magnesium triflate (Mg(CF3SO3)2) with 100≥ n ≥2 (where n, composition, is the molar ratio of oxyethylene repeat units per Mg2+ ion) have been characterized by Fourier transform infrared and Raman spectroscopy to elucidate the Mg2+/POE, Mg2+/urethane, Mg2+/CF3SO3 − and hydrogen bonding interactions. The Mg2+ ions bond to POE chains and to the carbonyl oxygen atoms of the urethane linkages over the whole range of salt content studied. A crystalline POE/Mg(CF3SO3)2 complex of unknown stoichiometry is formed at n =5. “Free” and weakly coordinated CF3SO3 − ions are present in all the materials examined. Contact ion pairs emerge at n ≤20 and higher ionic aggregates appear at n ≤5.