Iminoformylation Reaction of Substituted Crotonnitriles. III. Stereochemistry and Intramolecular Mobility of 4‐Amino‐1.1‐dicyano‐buta‐1.3‐dienes1H‐ and13C‐n.m.r. spectroscopic investigations show the preference of s‐trans configuration and the push‐pull character of the investigated 4‐amino‐1,1‐dicyano‐buta‐1,3‐dienes. Dynamic1H‐ and13C‐n.m.r. data for the rotation process about the CN bond are determined. The activation energies are discussed with respect to electronic and steric effects of