The intercalation chemistry of some layered ternary chalcogenides has been investigated. The reaction of n-butyllithium with Ta2NiSe5 and Ta2PdSe6 affords the compounds Li2Ta2NiSe5 and LiTa2PdSe6. X-ray powder diffraction data are indicative of significant structural changes upon intercalation. The addition of Cu to the NbPdS system has produced the compound Nb2Pd0.74Cu0.22S5. This compound has been characterized by single-crystal X-ray diffraction methods (monoclinic, C32hC2/m, a = 12.208(6), b = 3.286(2), c = 14.851(8) A ̊, β = 101.27(2)°). The compound is part o f an isomorphous series of nonstoichiometric metallic conductors with the Nb2Pd0.71Se5 structure, but it differs from its congeners in having Cu atoms in between the layers. The structural chemistry and reactivity associated with the van der Waals' region in these ternary compounds is compared with that of the binary Nb and Ta chalcogenides.