Single-crystal, X-ray crystallographic studies of ClSO₂(CF₂)₄SO₂Cl and ClSO₂(CF₂)₆SO₂Cl reveal the first examples of S–Cl⋯O halogen bonding complemented by short F⋯F contacts between neighbouring chains that result in stabilized crystals. These compounds allow the study of intermolecular associations involving halogens where hydrogen bonding cannot be operative.