The title compound, C13H8Cl4N5O6P3, consists of a non-planar trimeric phosphazene ring and a bulky 2,2′-methylenebis(4-nitrophenoxy) side group which predominantly determines the molecular shape. With respect to the corresponding values in the reference compound N3P3Cl6, the endocyclic angle around one P atom is the same, but the exocyclic angle is increased, while the endocyclic and exocyclic angles about another P atom are both decreased. This situation is different from that in other reported phosphazene derivatives.