The dehydration behavior of two synthetic, unsubstituted and cobalt-substituted, zincophosphates (one a sodalite analog and the other a new, hexagonal phase) was studied by TG/DTG and DSC. TG/DTG curves of the sodalite phases were very similar, exhibiting only one major weight loss that shifted to higher temperatures with increased amount of cobalt substitution. The profiles of the corresponding DSC curves, however, differed considerably among themselves. TG/DTG curves of hexagonal phases showed a more complex, multi-step dehydration behavior; the corresponding DSC curves also exhibited multiple endotherms. An explanation of these phenomena is given in terms of the specific arrangement of water molecules within a particular zincophosphate framework.