AbstractTwo‐ and three‐bond deuterium isotope shifts (2Δ and3Δ) of the13C nuclear shielding were measured for a series ofpara‐substituted anilines and acetanilides, in which the amide NH or the amine NH2hydrogens were partially exchanged with deuterium. The results show that when strong electron‐donating groups are present at theparaposition in acetanilides, the2Δ(C‐1) isotope shifts are smaller than the3Δ(C‐2,6) isotope shifts. Empirical correlations that relate2Δ isotope shifts with1H(NH),13C(C‐ipso),15N(NH2or NH),17O(CO) NMR chemical shifts and with3Δ isotope shifts are presented. The results are interpreted in each series as depending on the characteristic nitrogen lon