The pyrolysis and combustion characteristics of carbons prepared by carbonization of porphyrin-and metalloporphyrin-containing (or phthalocyanine-and vanadyl phthalocyanine-containing) precursors are reported. All the metals studied-V, Fe, Co and Cu-catalysed the combustion of the carbons, regardless of heat-treatment temperature. In general, the reactivities of all the carbons decreased with increasing heat-treatment temperature, and a compensation effect on the rate was observed, with both the activation energies and the pre-exponential factors decreasing. The metals have a marked influence on the release of nitrogen species during pyrolysis. Less HCN and CH3CN are released in the volatiles for metalloporphyrin-derived carbons than for porphyrin-derived carbons. The vanadyl system was also studied for nitrogen release during combustion. Less fuel-N is converted to NO and more is converted to N-2 and HCN during combustion of this carbon.