Abstract: The influences (Dilution Shift Effect) of sample concentration on ~1H NMR spectra and spin-lattice relaxation times in benzo-azacrown-ether (CE) -CDCl_3 solutions were discussed in this paper. It was considered that the formation of hydrogen bond complex between CE and CDCl_3 is not the major cause leading to Dilution Shift Effect. Based on experiments, a reaction mechanism for CE in CDCl_3-“tertiary amine-tertiary amino salt exchange” was proposed, which has successfully explained the Dilution Shift Effect. The equilibrium constants K_2[(2.2±0.4)×10~(-2) mol L~(-1), (1.9±0.4)×10~(-2) mol L~(-1) and (1.3±0.4)×10~(-2) mol L~(-1) respectively] and exchange rate constants k[4500±1000 s~(-1), 15000±3000 s~(-1) and 6000±1500 s~(-1) respectively] for this mechanism of “tertiary amine-tertiary amino salt exchange” of I, II and III (see experimental section) were obtained through simulation of chemical shift and line shape of ~1H NMR spectra of CE in CDCl_3. Also, the effects of substitute groups of α—C to N on the Dilution Shift Effect were discussed.