Despite the high potential of the azo-coupled fused tricyclic 1,2,3,4-tetrazine ring system in energetic materials, there are only very limited examples of such a scaffold. The oxidation of di-N-amino compound 1 with tert-butyl hypochlorite (tBuOCl) gives rise to the unexpected chloro-substituted compound 2, which behaves as a precursor to the structurally attractive diazido/nitro-substituted fused tricyclic 1,2,3,4-tetrazine 3. The structure is well characterized and is supported by single-crystal X-ray diffraction. Compound 3 was found to be a highly energetic and sensitive explosive.