AbstractThe13C NMR spectra of 40 vicinally substituted 2‐ and 3‐nitropyridines were recorded. The observed chemical shifts are, in general, non‐additive. These results are discussed in terms of the effects of 2‐, 3‐ and 4‐substitutents on the ring carbons and of the position of the fixed nitro group and the substituent. The chemical shifts of theparacarbon, with respect to the substitutent, follow well the dual substituent parameter approach, which shows their electronic origin. However, the substituent chemical shifts of bothipsoandorthopositions can be rationalized, in terms of multiple parameter substituent correlation analysis, only on a approx