Nitrogen-containing polycyclic aromatic compounds (NPAC) emitted from two types of coal throughout secondary pyrolysis were classified according to fused aromatic ring number. During the very early stages of secondary pyrolysis, neutral NPAC decrease due to direct conversion to soot, similar to what has previously been observed for neutral PAC. As secondary pyrolysis proceeds, neutralization of more polar compounds causes an increase in the nonpolar NPAC, and the 3- and 3-ring NPAC exhibit a greater persistence than their corresponding neutral PAC analogues. Unique trends in 2-ring NPAC for both coal tars during the latter half of secondary pyrolysis, reported here for the first time, can be attributed to a reaction between acetylene and pyridine. Although soot formation is not significantly affected by the small quantity of NPAC present, the observed stability of NPAC under severe thermal conditions suggests that they may be present in emissions.