[5,5]‐Fused Heterocycle‐Bridged Bistetrazoles Enable High‐Energy and Insensitive Nitrogen‐Rich Materials

ABSTRACT Constructing bridged bistetrazole frameworks is an established strategy for tuning the performance and safety of nitrogen‐rich energetic materials. Here, we introduce a rigid [5,5]‐fused heterocycle as a structural bridge to access a family of bistetrazole‐based energetic compounds ( 2 , 5 , 6 , and 2a–2d ) through a concise and efficient synthetic route. These compounds exhibit high density ( ρ = 1.79–1.90 g cm ⁻³ ), excellent thermal stability ( T _d = 181–354°C), and favorable mechanical insensitivity ( IS = 16–30 J; FS = 240–360 N). Notably, the energetic salts 2c ( D _v = 9285 m s ⁻¹ ) and 2d ( D _v = 9551 m s ⁻¹ ) outperform the benchmark explosive RDX ( D _v = 8814 m s ⁻¹ ). These results demonstrate that [5,5]‐fused‐ring bridging provides an effective design principle for achieving synergistic enhancement of energy density and safety, offering a powerful platform for the development of next‐generation energetic materials.