1-Allyl-6-nitro-1H-indazole

The fused five- and six-membered rings in the title mol­ecule, C₁₀H₉N₃O₂, are essentially coplanar, the largest deviation from the mean plane being 0.012 (1) Å for the C atom linked to the nitro group. The fused-ring system makes a dihedral angle of 11.34 (6)° with the nitro group, leading to a syn-periplanar conformation. The plane through the atoms forming the allyl group is nearly perpendicular to the indazole fused-ring system, as indicated by the dihedral angle of 73.3 (5)°. In the crystal, each mol­ecule is linked to its symmetry equivalent about the center of inversion by pairs of non-classical C—H...O hydrogen bonds, forming an extended tape motif parallel to the (-12-1) plane.