6-(3,5-Dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetra­zin-3(2H)-one

The title compound, C₇H₈N₆O, represents the keto form and adopts a nearly planar structure (r.m.s. deviation of the non-H atoms = 0.072 Å). In the crystal, mol­ecules form spiral chains along the c axis by N—H...N hydrogen bonds. The chains are linked to each other by weak C—H...O hydrogen bonds, forming a three-dimensional framework.

3-Methyl-4-(2-phenyl-1,2,4-triazolo[1,5-a]pyrimidin-7-yl)furazan

In the title mol­ecule, C₁₄H₁₀N₆O, the planes of the methyl­furazan fragment and the phenyl ring attached to the triazolo­pyrimidine bicycle are twisted from the mean plane of the bicycle at angles of 45.92 (5) and 5.45 (4)°, respectively. In the crystal, π–π inter­actions, indicated by short distances [in the range 3.456 (3)–3.591 (3) Å] between the centroids of the five- and six-membered rings of neighbouring mol­ecules, link the mol­ecules into stacks propagating along the c-axis direction.