N'-[(E)-4-(Diethyl-amino)benzyl-idene]-4-nitro-benzohydrazide monohydrate.

In the title compound, C(18)H(20)N(4)O(3)·H(2)O, the two aromatic rings are linked through a methyl-idenehydrazide fragment, which is fully extended with C-C-N-N, C-N-N=C and N-N=C-C torsion angles of 179.4 (2), 174.7 (2) and 178.3 (2)°, respectively. The dihedral angle between the two aromatic rings is 7.01 (8)°. In the crystal structure, the water of hydration is involved in extensive hydrogen bonding. Inter-molecular O-H⋯O, N-H⋯O and O-H⋯N hydrogen bonds link the components of the structure into a two-dimensional network and additional stabilization is provided by weak inter-molecular C-H⋯O hydrogen bonds.