To prepare a family of functionalized polymers, we investigated the nucleophilic substitution reaction of poly(epichlorohydrin) (PECH) and its 1:1 copolymer with ethylene oxide (PECH-PEO) with a series of substituted phenolates with electron-withdrawing and electron-donating groups. The basic character of the phenolates involves an undesired dehydrochlorination side-reaction and the subsequent chain scission process. Depending on the characteristics of the substituent directly attached to the phenolate, polymers with different proportions of substituted and vinylic units are obtained. In most cases, the modification is not quantitative and chloromethylated units remain in the final polymer. Similarly, the extent of the cleavage reaction depends on the phenolate. The functional polymers have been structurally characterized by C-13-NMR spectroscopy. Their thermal properties have been evaluated by differential scanning calorimetry and thermogravimetry.