Host molecules based on triarylantimony(III, V) and triarylbismuth (III, V) species were synthesized and characterized. Investigations into the clathratogenic properties of these species were conducted through TGA screening experiments which were supplemented with 1H NMR and both single crystal and powder X-ray diffraction methods. The crystal structures of many of the newly discovered inclusion and guest-free phases are presented and analyzed. Tri(α-naphthyl)antimony (SbNap3) is able to enclathrate at least three guest molecules (benzene, THF, and DMF) and will oxidize in ethylbenzene and p-xylene to form inclusion crystals of its oxide, (SbNap3O)2. SbNap3X2 were not found to form inclusion compounds. Trimesitylantimony di(pseudo)halides (SbMes3X2) enclathrate a wide variety of guest solvents including aromatic compounds, aliphatic hydrocarbons as well as some polar solvents. SbMes3X2 demonstrate high selectivity when crystallized from mixtures of benzene, toluene and xylenes. Bismuth analogues of the aforementioned species performed similarly to their antimony counterparts with respect to their clathratogenic properties. Bismuth(V) species, however, suffered from a lack of chemical stability, which prevented detailed studies on these compounds. This thesis represents the first comprehensive study of host materials based on either antimony or bismuth compounds.