The νCOIR analysis of α-(p-phenylsulfonyl)-p-substituted acetophenones X-øC(O)CH2S(O)2ø-Y1–8, being X and Y = NO2, H and OMe substituents, supported by Molecular Mechanics data of the α-methylsulfonylacetophenone (model compound), indicates the existence of thecis/gaucherotational isomerism. The less polargouche2rotamer is the more stable (conc. ≅ 90%) and the more polarcisrotamer is the less stable one along the series. Compounds 4 (X = Y = H) and 3 (X = H, Y = OMe) present another less stable and rather polargauche1rotamer. The almost constant carbonylgauche2shifts (Δνg2) together with the quasi-invariability of thecis/gaucheratios, when X varies and Y is fixed, indicates a very nearly constant summing up of π*CO/[sgrave]C-SCO2and π*CO/[sgrave]C-SCO2orbital interactions. The progressive stabilization of thegauche2rotamer when X is fixed and Y changes from NO2to OMe substituents, along with the parallel decrease of the positive sulfonyl asymmetric frequency shifts (ΔνSO2(as)) is discussed in terms of the progressive contribution of the O(SO2) → C(CO)electrostatic and charge transfer interactions. Additional support for the proposed interactions is given by the large NAE mean value for the α-methylene carbon chemical shifts together with the upfield shift of the β-ketosulfones mean carbonyl carbon chemical shifts in relation to that of the β-ketosulfoxides.