In the title compound, C(10)H(7)N(3)O(3), the dihedral angle between the two aromatic rings is 87.5 (1) Å; their ipso-C atoms subtend an angle of 117.4 (1)° at the ether O atom.
In the title compound, C(11)H(10)N(2)O, the aromatic rings make a dihedral angle of 76.3 (1)°. The C-O-C angle at the ether atom is widened to 117.79 (9)°.
In the title compound, C(10)H(9)N(3)O, the organic rings linked to the ether O atom make a dihedral angle of 76.8 (1)° and the C-O-C angle is widened to 119.07 (15)°. In the crystal, adjacent mol-ecules are connected by an N-H⋯N hydrogen bond, generating a chain running parallel to the b axis. The crystal is a non-merohedral twin with a ratio of twin components of 0.508 (3):0.492 (3).
The title compound, C(11)H(10)N(2)O, crystallizes with two mol-ecules in the asymmetric unit. The angle at the ether O atom is widened to 118.13 (15)° [117.89 (16)° for the second mol-ecule in the asymmetric unit]; the six-membered rings subtend a dihedral angle of 84.3 (1)° [87.4 (1)° in the second mol-ecule].
There are two molecules in the asymmetric unit of the title compound, C(10)H(9)N(3), with inter-ring dihedral angles of 31.1 (1) and 35.3 (1)°. The bridging C-N-C bond angles are 128.2 (1) and 129.1 (1)°. In the crystal, the two independent mol-ecules are linked into a dimer by two N-H⋯N hydrogen bonds.
In the title compound, C(14)H(10)N(2)O, the organic rings are inclined at an angle of 86.1 (1)°. The angle at the ether O atom is widened to 117.18 (14)°.