pi-Stacked hydrogen-bonded sheets in N,N'-bis(4-nitrobenzylidene)ethane-1,2-diamine and pi-stacked hydrogen-bonded chains in N,N'-bis(4-nitrobenzylidene)propane-1,3-diamine.

Molecules of N,N'-bis(4-nitrobenzylidene)ethane-1,2-diamine, C16H14N4O4, (I), lie across centres of inversion in space group P2(1)/n and are linked into (10-1) sheets by a single C-H...O hydrogen bond [H...O = 2.40 A, C...O = 3.2166 (13) A and C-H...O = 146 degrees ]; these sheets are linked into a three-dimensional array by a single aromatic pi-pi stacking interaction. Molecules of N,N'-bis(4-nitrobenzylidene)propane-1,3-diamine, C17H16N4O4, (II), lie across twofold rotation axes in space group C2/c and are linked into chains of spiro-fused rings by a single C-H...O hydrogen bond [H...O = 2.54 A, C...O = 3.267 (2) A and C-H...O = 130 degrees ]; these chains are linked into sheets by a single aromatic pi-pi stacking interaction.