Polymer-supported hexaethylene glycol substituted imidazolium salts (PS[hexaEGim][OMs] and PS[dihexaEGim][OMs]) were prepared, and were demonstrated to act as highly efficient heterogeneous catalysts in various nucleophilic substitution reactions using the corresponding alkali metal salts. Furthermore, it was observed that PS[hexaEGim][OMs] could indeed be reused repeatedly without the loss of its catalytic activity in the nucleophilic fluorination using KF, affording the corresponding product in a high yield (approximately 95%) in each cycle.