13C NMR assignments have been made for a series of 36 α‐ and 3,4‐dehydroretinoids with different substituents (alcohol, ester, aldehyde and acid) and for their separated E and Z geometrical isomers. The assignments were made by using 2D heteronuclear‐correlated NMR experiments. From the chemical shift data of 24 systematically related retinoids, empirical chemical shift changes due to four polar end groups (alcohol, aldehyde, carboxylic acids and esters), three chain configurations (all‐E, 9Z and 13Z), and two ring substitutions (2,6,6‐trimethyl‐cyclohex‐2‐enyl and 2,6,6‐trimethylcyclohexa‐1,3‐dienyl) were determined. All trends were found to be independent of each other, except for the dependence of the chemical shift change of the 13Z‐isomers on the polar end groups. The chemical shift changes were used to predict the chemical shifts of other retinoids based on two different ring structures (2,6,6‐trimethylcyclohexenyl and 4‐methoxy‐2,3,6‐trimethylphenyl). Copyright © 1987 John Wiley & Sons Ltd.