Treatment of 5-sulfosalicylic acid (H₃Ssal) with BiPh₃ results in the formation of the first dianionic carboxylate–sulfonate bismuth complex, [PhBi(HSsal)H₂O]_∞1a, and its ethanol analogue [PhBi(HSsal)EtOH]_∞1b (space groupP2₁/c), while Bi(OAc)₃ gives the mixed monoanionic and dianionic complex, {[Bi(HSsal)(H₂Ssal)(H₂O)₃]₂·2H₂O}_∞2 (space groupP). The three complexes are all polymeric in the solid state as determined by single crystal X-ray diffraction, with extended frameworks constructed from dimeric [Bi(HSsal)]₂, 1a and 1b, or from [Bi(HSsal)(H₂Ssal)]₂ units, 2. The heteroleptic bismuth complexes 1a and 2 display remarkable aqueous solubility, 10 and 2.5 mg ml⁻¹ respectively, resulting in a clear solution of pH 1.5. In contrast, 1b is essentially insoluble in aqueous environments. All three complexes show significant activity against the bacterium Helicobacter pylori of <6.25 μg ml⁻¹.