Despite the demands of the stronger hydrogen-bonding inter­actions present in the crystal structures of the title compounds, C₁₆H₁₀N₈ and C₁₆H₁₂N₆O.H₂O, T-shaped and shifted π-stacked arrangements of aromatic moieties are preferred, leading to herringbone and/or π-stacked crystal-packing motifs. Therefore, in both these compounds the crystal packing is in accordance with the theory of arene–arene interactions being dominated by electrostatics.