Carbazole-based receptors functionalized with two sulfonamide groups have been synthesized and their properties as anion receptors have been evaluated. The receptor with bis(trifluoromethyl)aniline groups has shown a very high affinity for halide ions, especially remarkable as only two hydrogen bonds are formed in the complexes. ¹H NMR and fluorescence titrations have been carried out and binding constants up to 7.9 × 10⁶ M⁻¹ have been reached. X-ray structures have been obtained and a modelling study has shown the possible reasons for the large affinity of these compounds for halide anions.