Exploring heat-resistant explosives that are easy to synthesize is a major challenge in the research of energetic materials. In this study, two novel fused-ring energetic compounds, namely 3,6-dinitropyrazolo1,5- a pyrimidine-5,7-diamine ( 4 ) and 5-amino-3,6-dinitropyrazolo1,5- a pyrimidin-7(4 H )-one ( 5 ), were successfully prepared via a simple synthetic method. In addition, their structure, thermal stability, mechanical sensitivity and detonation performance were fully explored. Noteworthily, compounds 4 and 5 both exhibit excellent thermal stability ( T D (4) = 325 °C and T D (5) = 291 °C), particularly compound 4 , which features an "amino-nitro-amino" arrangement similar to that of TATB and exhibits a high density of 1.88 g cm −3 and a greater thermal decomposition temperature than hexanitrostilbene (HNS, 316 °C). In addition, due to the aza-fused structure, 4 and 5 possess higher positive heats of formation (332.9 kJ mol −1 and 181.4 kJ mol −1 ) than LLM-105 (11.0 kJ mol −1 ). These advanced features endow 4 and 5 with superior detonation performance ( V d (4) = 8338 m s −1 and P (4) = 30.7 GPa; V d (5) = 8097 m s −1 and P (5) = 29.8 GPa) than TATB ( V d = 8179 m s −1 and P = 30.5 GPa) and HNS ( V d = 7170 m s −1 and P = 21.8 GPa). This study enriches prospects for the molecular design and crystal engineering of novel energetic materials with admirable molecular stability. Introducing the structural characteristics of TATB into the fused structure is a promising strategy for preparing high-energy heat-resistant explosives.