Novel calix [4] arene-based anion receptors 1–3 with bis-squaramide moieties were designed and synthesized. Their sensing properties with various anions were investigated by UV–vis, ESI-MS, and 1H NMR spectra. The experimental results revealed that there were two types of interaction modes where receptor 1 bound biologically important H2PO4−, F−, and AcO− ions selectively over other anions in the hydrogen bonding interaction mode, ...