2,4-Difluorobenzaldehyde benzoylhydrazone and 2,4-dichlorobenzaldehyde benzoylhydrazone are isostructural at 120 K with Z' = 2: complex sheets built from N-H...O, C-H...O and C-H...pi(arene) hydrogen bonds.

At 120 K, 2,4-difluorobenzaldehyde benzoylhydrazone, C14H10F2N2O, (I), and 2,4-dichlorobenzaldehyde benzoylhydrazone, C14H10Cl2N2O, (II), are isomorphous and isostructural in P2(1)/n with Z' = 2. In each structure, eight independent hydrogen bonds, viz. two of N-H...O type, five of C-H...O type and one of C-H...pi(arene) type, link the molecules into complex sheets, within which two independent one-dimensional substructures can be identified.