The synthesis of a new class of carbazole based macrocycles via [3 + 1] acid-catalyzed condensation is reported. Spectroscopic investigations and computational studies imply that these macrocycles have a large influence on the electronic structure in comparison to previously reported carbazole based macrocycles. Macrocycle 8 bearing a furan ring reversibly binds aqueous Hg2+ with high affinity over other Mn+ ions. The limit of detection (LOD) is ca. 100 nM. Hg2+ binding was confirmed via X-ray diffraction analysis.