The tetralactam series (1a-4c) and the two acyclic compounds (5 and 6) were analysed for their ability to bind to Cl -anions and F -anions using 1 H-NMR binding studies. Host solutions in DMSO-d6/H2O (0.5%) of a constant receptor concentration (1 mM) were used to make the guest solutions, containing the titrant guest anion as the TBA + salt. During the binding studies, the guest solutions were titrated into the host solution, causing stepwise increases in the concentration of the anionic guest. The changing chemical shifts (ppm) of the resonances attributed to the protons of the host were tracked and inputted into the BindFit web applet to produce binding constants (Ka, Table ). For further synthetic methods, see the experimental procedures section or for information on the fitted experimental data, including errors and associated spectra, see Table , Figure -S79 in the ESI.