2,4-Dinitroanisole, CTH6N2Os, Mr= 198, monoclinic, P21/n, a=8.772(2), b= 12.645 (2), c = 15.429 (4)A, fl= 81.89 (2) ° , V= 1694 A 3, Z= 8, D m not determined, Dx= 1.56 g cm -3, 2(MoK~q)= 0.7093 A, /t = 1.26 cm -~, F(000) = 816, T= 298 K, R r = 0.075 for 1916 observed reflections. 2,6-Dinitroanisole, CTH6N205, Mr=198, triclinic, P1, a= 3.854 (1), b = 7.736 (2), c= 14.476 (4) A, a= 89.25 (2), fl=86.97 (2), y= 75.59 (2) ° , V=417 A 3, Z = 2, D m not determined, D x= 1.58 g cm -3, 2(Mo Kch) = 0.7093 A, g = 1.28 cm -I, F(000) = 204, T= 298 K, R F = 0.069 for 1046 observed reflections. In the 2,4-dinitro compound, the two independent methoxy groups make torsion angles of 5 and 13 o with the ring planes, whereas in the 2,6-dinitro compound the angles are 72 and 79 ° . These results agree with those of related crystal structures. The rate of replacement of methoxy with an amino substituent appears to be correlated with out-of-plane twist of the methoxy group.