Thermal stability and high-temperature degradation of pristine bisazafullerene (C59N)2 were analyzed by infraredand Raman spectroscopy in the temperature range from 300 to 745 K. The spectra showed a reversibletemperature dependence up to 550 K. For higher temperatures an irreversible degradation into disorderedgraphite was found. Approximately 55% of the material resisted a thermal treatment of 745 K for severalhours. A mechanism involving a low stationary concentration of C59N• monomer radical species and a slowgraphitization is proposed for the thermolysis of the material. The remarkable thermal stability of pristinebisazafullerene (C59N)2 is ascribed to the low stability of the C59N• monomer radical species, the high activationenergy for graphitization, and the absence of other reaction partners under high vacuum conditions.