Key indicatorsSingle-crystal X-ray study T = 294 K Mean (C-C) = 0.004 Å R factor = 0.043 wR factor = 0.127 Data-to-parameter ratio = 12.3For details of how these key indicators were automatically derived from the article, see

The title compound, C17H15N3O3, was prepared from 1-(2-nitro­phen­yl)-3-phenyl­prop-2-en-1-one and hydrazine. The dihedral angle between the benzene and phenyl rings is 74.55 (2)°. The pyrazoline ring is in a slight envelope conformation with the C atom bonded to the phenyl ring forming the flap. In the crystal structure, weak inter­molecular C—H⋯O hydrogen bonds connect mol­ecules into chains along [100].

The title compound, C22H19FN2, was prepared by reacting phenylhydrazine with 1‐(4‐fluorophenyl)‐3‐(p‐tolyl)prop‐2‐enone. The pyrazoline ring forms a dihedral angle of 5.2 (3)° with the phenyl ring, 8.8 (1)° with the fluorophenyl ring and 80.7 (2)° with the p‐tolyl ring.

The title compound, C22H19ClN2, was prepared by the reaction of phenylhydrazine and 1‐(4‐chlorophenyl)‐3‐(4‐methylphenyl)prop‐2‐en‐1‐one. The pyrazoline ring forms dihedral angles of 1.50 (5)° with the phenyl ring, 8.44 (2)° with the chlorophenyl ring and 80.07 (1)° with the tolyl ring.