Reverse atom transfer radical polymerization was first used to successfully synthesize polyacrylonitrile under microwave irradiation. FeCl3, coordinated by isophthalic acid, was used as the catalyst, and 2,2'-azobisisoheptonitrile was used as the initiator. N,N-Dimethylformamide was used as the solvent to improve the solubility of the ligand. Under the same experimental conditions, the apparent rate constant under microwave irradiation was higher than that under conventional heating. The polymerization not only showed the best control of the molecular weight and its distribution but also provided a rather rapid reaction rate with the [acrylonitrile]/ [2,2'-azobisisoheptonitrile]/[FeCl3]/[isophthalic acid] ratio of 300: 1 :1 : 2. The polymers obtained were used as macro-initiators to initiate the chain extension and successfully synthesize acrylonitrile polymers with a molecular weight higher than 50,000 and a narrow polydispersity as low as 1.30. (c) 2007 Wiley Periodicals, Inc.