Novel chemical structures originally proposed as new thermally insensitive explosives were certain zero- to low-hydrogen-content, polynitro, polycyclic heteroaromatic compounds based on nitrogenous heterocycles. The proposed compounds were expected to be high-density materials with explosive yields in the RDX-to-HMX range, but with high melting points, good shock sensitivity, and significantly better thermal stabilities. Originally proposed candidates incorporated 3,6-dinitropyridazine as a structural feature, Based on the experimental results and on conclusions drawn from a careful consideration of principles of reactivity of this general class of compound-polynitroazines-important lessons were learned that are applicable to future choices of practical new energetic materials targets. A conclusion is drawn that the intractability of certain polynitroazine target compounds unavoidably arises from an extraordinary susceptibility to ubiquitous environmental contaminants such as water. The recognition of this structure-property relationship should have an important payoff toward future choices of target compounds.