To further test the validity of 1 JC-H compared to ETS-NOCV, we expanded our study to include more carbenes, adding 48 structures of classes A-I, which include positively charged carbenes, to the original 40 compounds. The results confirm the strong correlation between ETS-NOCV and 1 JC-H for these classes, except for those with Cl substitutions (Figure ; R 2 = 0.90 excluding the three chlorinated compounds 105, 113 and 117).