Abstract: | The crystal structures of the four isomeric organic salts 4‐aminopyridinium 2‐chloro‐4‐nitrobenzoate, (I), 4‐aminopyridinium 2‐chloro‐5‐nitrobenzoate, (II), 4‐aminopyridinium 5‐chloro‐2‐nitrobenzoate, (III), and 4‐aminopyridinium 4‐chloro‐2‐nitrobenzoate, (IV), all C5H7N2+·C7H3ClNO4?, are presented. Compound (I) has one intramolecular hydrogen bond, one intermolecular C—H?O hydrogen bond and π–π‐stacking interactions. Compound (II) has N—H?O, C—H?O and C—H?Cl hydrogen bonds, and Cl?O—C electrostatic interactions. Compound (III) has N—H?O and C—H?O hydrogen bonds. Compound (IV) has a π–π‐stacking interaction, but no C—H?O hydrogen bonds. |