Divalent metal salts of mono(hydroxyethy1) phthalate are useful starting materials for synthesis of ionic polymers into which metal is firmly incorporated. This article surveys a series of polymers that have been synthesized by using metal salts. The salts can react with compounds having functional groups capable of reacting with hydroxyl groups. By polyaddition reactions of the salt-diol with diisocyanates in dimethylformamide, metal-containing polyurethanes, polyurethane-ureas, and isocyanurate-type crosslinked polyurethanes are obtained. In polycondensation reactions of the salt-diols with anhydrides, some systems give unsaturated polyesters soluble in styrene. Meanwhile, polyaddition reactions of systems of the salt-anhydride-epoxide give metal-containing polyesters containing ionic links in the main chain. The metal carboxylate groups of the salts catalyze the reactions in this case. The reactions have offered a commercially favorable synthetic route. Through the proper selection of components, various types of metal-containing unsaturated polyesters, cured resins, and cured rubbers are obtained. The effect of introducing metal on their physical and other properties results, and, in addition, generally Mg is more effective than Ca in improving the properties of the polymers.