The title compound TNDFIW, C(8)H(8)N(10)O(10), is a caged heterocycle substituted with four nitro and two formyl groups. It is related to the hexa-azaisowurtzitane family of high-density high-energy polycyclic cage compounds. Four nitro groups are appended to the four N atoms of the two five-membered rings, while the other two formyl groups are attached to the two N atoms of the six-membered ring, which adopts a boat conformation. The compound has a cage structure which is constructed from one six-membered and two five-membered rings which are closed by a C-C bond, thus creating two seven-membered rings. There are a number of close intermolecular contacts [O⋯O = 2.827 (5), 2.853 (4) and 2.891 (5) Å; O⋯N = 2.746 (2) and 2.895 (2) Å] The calculated density of TNDFIW is 1.891 Mg m(-3).