Abstract: A new imidazole polymer salt was synthesized in order to develop a high efficiency phase-transfer catalyst for multi-phase reactions. The polymer salt was prepared easily by co-polymerization of 1-1′-(1,4-butamethylene)bis(imidazole) and 1,2-dibromoethane, and has the properties of excellent chemical and thermal stability and high ionic conductivity. It was applied as phase-transfer catalyst in the fluorination of chloronitrobenzenes under the irradiation of microwave and gave excellent yields of corresponding fluoronitrobenzenes. In addition, the enhanced mechanism of microwave was studied and found “non-thermal” effect was a great factor. [Copyright &y& Elsevier]