A detailed characterization of the charged states of C84 fullerene isomers by in-situ ESR-UV/Vis/NIR spectroelectrochemistry is presented.The fullerene C84 is the third most abundant fullerene extractable from an arc-processed soot.Unlike in C60 the 84 carbon atoms in C84 can form up to 24 isomeric structures satisfying the isolated pentagon rule (IPR).It is generally agreed that the D2(Ⅳ) and D2d(Ⅱ) isomers are the two most abundant ones usually yielded in the ratio 2:1.The full separation of both C84 major isomers as well as of some minor isomers was first achieved by the recycling HPLC by H.Shinohara and his group.The authors reported the first and only electrochemical and spectroscopic study of some isomers.