Conduction mechanism of Li+ cation in a stoichiometric LiInI4 was studied experimentally. In general, the interpretations of the Li-7 NMR powder spectrum and its temperature dependence are not straightforward because of a broadening due to not only dipole-dipole interactions but quadrupole effect (Li-7, I=3/2). In this NMR experiment on LiInI4, the quadrupole effect and the dipole-dipole interactions could be discussed separately using a single crystal. Since LiInI4 belongs to a monoclinic crystal, two pairs of satellite transitions (Delta m = 3/2 <-> 1/2 and -3/2 <-> -1/2) as well as a central transition (Delta m = -1/2 <-> 1/2) were observed for Li-7 NMR due to the first order quadrupole effect. Above 380 K, however, these two satellite pairs merged into one pair associated with the motional narrowing phenomenon. This finding directly suggests a site exchange of the Li+ between two crystallographically equivalent sites. The exchange rate (k(ex)) was estimated using a spectrum simulation of the coalescence phenomena and, furthermore, the bulk ionic conductivities were calculated as a function of temperature which agreed well to those from the complex impedance method. The site exchange phenomenon especially appeared on the single crystal NMR spectra was proved to be a good technique to evaluate ionic conductivity and its mechanism in solid. (C) 2011 Elsevier B.V. All rights reserved.