The reaction of an organic azide with an endohedral metallofullerene has been investigated for the first time. Isomeric [5,6)- and [6,6]-azafulleroids can be obtained from the thermal reaction of Sc3N@I-h-C-80 with 4-isopropoxyphenyl azide, while photoirradiation leads exclusively to the [6,6]-azafulleroid. An unprecedented thermal interconversion between the two isomeric azafulleroids has also been discovered.