AbstractAll the signals in the 13C NMR spectra of o‐carbonyl naphthol derivatives (i.e. o‐hydroxy aldehydes, o‐hydroxy methyl ketones and methyl esters of o‐hydroxy acids) are assigned on the basis of the additivity rule of substituent‐induced shifts and selective 13C{1H} hetero‐decoupling experiments [sometimes in the presence of Yb(fod)3]. The differences between the experimental chemical shifts and the values calculated on the basis of the additivity of substituent‐induced shifts are also given; these may be regarded as ‘intramolecular hydrogen bond‐induced shifts’.