Abstract: | The molecular dimensions of both 2‐amino‐6‐(N‐methylanilino)pyrimidin‐4(3H)‐one, C11H12N4O, (I), and 2‐amino‐6‐(N‐methylanilino)‐5‐nitropyrimidin‐4(3H)‐one, C11H11N5O3, (II), are consistent with considerable polarization of the molecular–electronic structures. The molecules of (I) are linked into a three‐dimensional framework by a combination of one N—H...N hydrogen bond, two independent N—H...O hydrogen bonds and one C—H...π(arene) hydrogen bond. The molecules of (II) are linked into ribbons containing three types of edge‐fused ring by the combination of two independent three‐centre N—H...(O)2 hydrogen bonds. |