This work investigates a simple synthetic method for producing fused dinitromethyl energetic compounds. Fused compound 2 has a high detonation velocity (9358 m s-1) close to that of the well-known high-energy-density explosive CL-20 (9455 m s-1), an extremely high density (1.97 cm-1), and acceptable sensitivity (IS = 8 J). The good thermal stability of 2 (Td = 181 °C) is rarely reported in the field of dinitromethyl-based high explosives. The results show that compound 2 is a promising candidate for high explosives and provide new insight into the synthesis of dinitromethyl compounds.