1-[5-(4-Chloro-phen-yl)-3-(4-hy-droxy-phen-yl)-4,5-dihydro-1H-pyrazol-1-yl]-ethanone.

In the title compound, C(17)H(15)ClN(2)O(2), the benzene rings form dihedral angles of 89.56 (5) and 5.87 (5)° with the mean plane of the pyrazoline ring (r.m.s. deviation = 0.084 Å). The dihedral angle between the two benzene rings is 87.57 (5)°. In the crystal, mol-ecules are linked by O-H⋯O and C-H⋯O hydrogen bonds into a helical chain along the c axis. Between the chains weak C-H⋯N and C-H⋯O inter-actions are present. The crystal studied was an inversion twin with a domain ratio of 0.72 (4):0.28 (4).