Although the vertical excitation energies of the n,* states depend on several factors of both the S0 and n,* states, the relative energies of isomeric heteroaromatics in their n,* states vary in dependence of the aromatic character of the residuals. For example, the n,* state of pyrazine (9) has a residual which is more aromatic than the n,* state of pyrimidine (8), with the first being lower in energy than the latter by 0.34 eV.