| Member | Definition | Role |
|---|
| cinnoline | An azaarene that is the 1,2-diaza analogue of naphthalene. The parent of the class of cinnolines. | cinnoline |
| hydralazine | The 1-hydrazino derivative of phthalazine; a direct-acting vasodilator that is used as an antihypertensive agent. | hydralazine |
| isoquinoline | An ortho-fused heteroarene that is a benzopyridine in which the N atom not directly attached to the benzene ring. | isoquinoline |
| phenanthridine | An azaarene that is the 9-aza derivative of phenanthrene. The parent of the class of phenanthridines. | phenanthridine |
| phenazine | An azaarene that is anthracene in which the carbon atoms at positions 9 and 10 are replaced by nitrogen atoms. | phenazine |
| phthalazine | An azaarene that is the 2,3-diaza analogue of naphthalene. The parent of the class of phthalazines. | phthalazine |
| pteridines | | pteridine |
| pyridine | An azaarene comprising a benzene core in which one -CH group is replaced by a nitrogen atom. It is the parent compound of the class pyridines. | pyridine |
| quinazolines | A mancude organic heterobicyclic parent that is naphthalene in which the carbon atoms at positions 1 and 3 have been replaced by nitrogen atoms. | quinazoline |
| quinoline | The simplest member of the quinoline class of compounds, comprising a benzene ring ortho fused to C-2 and C-3 of a pyridine ring. | quinoline |