We consider a 6-MR molecule to be aromatic in S0 if its MCI value is at least half the MCI value of benzene in S0 (i.e., 0.0716/2 = 0.0358). However, the vertically excited lowest triplet * state of benzene is multiconfigurational and is therefore not (easily) comparable to those of the lower-symmetry heterocycles. Instead, we used the MCI and EDDB values of the lowest 3 * state of pyridine, which is single-configurational and antiaromatic. This state is an antiaromatic reference with a total MCI value of -0.0005, and MCI-and MCI-components of 0.0023 and -0.0028, respectively. Thus, in the (anti)aromaticity assessments of the n,* states of a compound, we use two measures; (i) the ratio between the MCI( 3 n,*)tot and MCI(S0)tot of a specific compound and its deviation from 50%, representing nonaromaticity, and (ii) a comparison of the S0 or n,* state of a specific heteroaromatic with the aromaticity of benzene in S0 (aromatic reference) and the antiaromaticity of the triplet * state of pyridine (antiaromatic reference).