4-Methacryloyloxy-TEMPO free radical (1) is a chemically stable free radical having a nitroxide radical moiety. Its oxygen-centered radical and the related nitrogen-centered cation radical are stabilized by structural resonance. A reversible oxidation-reduction of
1 occurs by giving and receiving of one electron and forms the corresponding oxoammonium cation or aminoxyl anion. So,
1 can be used in the synthesis of oxidation-reduction polymers and magnetic polymers. Synthetic resins of
1 are expected to be used as light weight, soft materials.