The chromatographic properties of the clathrates formed by Ni(NCS) 2 (4-methylpyridine) 4, treated as representative of a large group of Werner MeX 2A 4 complexes able to form clathrates, were studied. As the compounds to be separated, o-, m-isomers of dinitrobenzene and bromonitrobenzen were used. It was found that the volume of the channels in the zeolite-like Ni (NCS) 2(4-methylpyridine) 4 structurer can vary by about 50%, owing to dilatation of the crystal structure related to the composition of the guest, and can be easily controlled by using a suitable composition of the mobile phase. The selectivity of chromatographic sorption as a function of dilatation—contraction of the clathrate structure and competitive clathration of the mobile phase components (elution power) is discussed.