The three title compounds, namely (Z)-1-(4,5-dinitroimidazol-1-yl)-3-morpholinopropan-2-one 2,4-dinitrophenylhydrazone, C(16)H(17)N(9)O(9), (IV), (Z)-3-morpholino-1-(4-morpholino-5-nitroimidazol-1-yl)propan-2-one 2,4-dinitrophenylhydrazone, C(20)H(25)N(9)O(8), (Va), and (E)-3-morpholino-1-(4-morpholino-5-nitroimidazol-1-yl)propan-2-one 2,4-dinitrophenylhydrazone tetrahydrofuran solvate, C(20)H(25)N(9)O(8).C(4)H(8)O, (Vb), have been prepared and their structures determined. In (IV), the C-4 nitro group is nearly perpendicular to the imidazole ring and the C-4-NO(2) bond length is comparable to the value for a normal single Csp(2)-NO(2) bond. In (IV), (Va) and (Vb), the C-5 nitro group deviates insignificantly from the imidazole plane and the C-5-NO(2) bond length is far shorter in all three compounds than C-4-NO(2) in (IV). In consequence, the C-4 nitro group in (IV) is easily replaced by morpholine, while the C-5 nitro group in (IV), (Va) and (Vb) shows an extraordinary stability on treatment with the amine. The E configuration in (Vb) is stabilized by a three-centre hydrogen bond.