Abstract
In the cation of the title mol-ecular salt, C(18)H(13)N(4)O(+)·Cl(-)·H(2)O, the dihedral angle between the mean planes of the 1,10-phenanthroline system and the phenol ring is 14.40 (19)°. The crystal packing is stabilized by O-H⋯O hydrogen bonds, weak N-H⋯Cl and O-H⋯Cl inter-molecular inter-actions and π-π stacking inter-actions [centroid-centroid distance = 3.6944 (13) and 3.9702 (12) Å].