The chemistry of high-energy-density materials (HEDMs) featuring multiple nitrogen-rich heterocyclic skeletons with energetic fragments has witnessed enormous growth since the process of manufacturing explosives successfully was improved by Alfred Nobel. In particular, the recent surge of interest in HEDMs is because of its wide application in the military and civilian fields. In this review, we provide a systematic introduction to the developments in heterocyclic nitrogen-rich energetic materials with various explosive groups in the form of tricyclic-based compounds. This review summarizes the recent efforts toward new HEDMs based on the synthetic route, crystal behavior and the structure–property relationship. Further studies on new nitrogen-rich heterocycles may be helpful to achieve a more sustainable chemical process, which could make a positive impact of chemistry, not only for HEDMs, but also in other fields.