S-EPMC10912976 - Evaluation of naked-eye sensing and anion binding studies in meso-fluorescein substituted one-walled calix[4]pyrrole (C4P)† † Electronic supplementary information (ESI) available: The supporting information contains material methods. Characterization part (1H-NMR, 13C-NMR, HRMS of all the synthesized compounds), anion sensing and anion binding studies spectra. Frontier molecular orbital distribution of C4P7 with various anions and their theoretically predicted FTIR spectra. See DOI: https://doi.org/10.1039/d3ra08362d