The concept of conjugation between formal double bonds separated by a formal single bond is frequently used to describe qualitatively the electron delocalization in π-electron systems. Whereas in carbon compounds the prerequisite for optimum conjugation is a rather strict, geometrical condition of exact or near coplanarity of the participating carbon atoms, the geometrical conditions are much more relaxed for third-row atoms if valence-shell d orbitals are involved in the bonding. In a family of sulfur compounds, N-sulfonylsulfilimines, the conjugation is virtually unaffected by large distortions of bond-rotation angles, leading to rotation-independent conjugation. Ab initio SCF-HF calculations, using an STO-3G ∗ basis set that includes d orbitals for the S atoms, provide evidence for such “flexible conjugation” and give an explanation for the experimentally observed interconversion of chiral conformers of molecules of the above family. The results are in agreement with experimental data and the qualitative conclusions of earlier, semiempirical calculations.