The chemical processes that result in self-assembly of nitride clusterfullerenes are largely unknown because in situ experimental studies are not possible by conventional arc plasma discharge techniques. Here, we report the gas-phase formation of Group III-containing nitride clusterfullerenes by laser vaporization of graphite-, metal-, and heteroatom-based starting materials, conducted by online chemical sampling techniques and analyzed by ultrahigh resolution 9.4 tesla Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Further, structurally defined clusterfullerenes are exposed to carbon vapor produced from graphite under characteristic physicochemical synthesis conditions to elucidate cluster-cage and structural effects on nanocarbon reactions that control formation.