Abstract: Two novel cryptands were synthesized by reaction of di-benzylamines of Two novel cryptands were synthesized by reaction of di-benzylamines of Bis(m-phenylene-26crown-8 and Bis(m-phenylene-32crown-10 with 5-tert-butyl-iso-phthaloyl dichloride. The structures of them were confirmed by NMR and ESI-MS spectra. The complexation behavior of the cryptand hosts with pyridine N-oxide guests were analyzed by ESI-MS and 1H NMR. The results shown that both of the cryptand hosts can bind the guests to form 1:1 complexes; for the same guest, the binding ability of host 10 (with larger ring cavity) is 23 times larger than that of host 5