The1H nuclear magnetic resonance spectral parameters are reported for 4.0 mol% solutions of 2-(4-chlorophenylthio) benzaldehyde in CS2/C6D12and acetone-d6at 300 K. In CS2theO-synconformer is 36% abundant, rising to 50% in acetone-d6. These abundances are compared to those of theO-synandO-transconformers of 2-(alkylthio) benzaldehydes in CCl4, solution. On the basis of coupling constants and chemical shifts it is concluded that the skew conformer of the title compound is very likely the one of minimum energy in both solutions. In the skew conformer the plane of the 4-chlorophenyl group lies perpendicular to the CSC plane and also to that of the other aromatic moiety. It is suggested that theinteraction is rather weak and that the population of theO-synconformer is controlled by the orientation of the mainly 3plone-pair orbital on sulfur. At best, theinteraction is attractive only when the 3porbital lies perpendicular to the plane of the formyl group. The skew conformation of the title compound is contrasted to the skew conformation of 2-hydroxyphenyl phenyl sulfide in which, however, the role of the two aromatic planes is reversed; the 3porbital now lies in or near the plane of the phenyl group COH due to an attractiveinteraction.