Pyrrolidinium-2-carboxyl­ate–4-nitro­phenol (1/2)

In the title compound, C₅H₉NO₂·2C₆H₅NO₃, the pyrrolidine ring of the pyrrolidinium-2-carboxyl­ate zwitterion adopts a twisted conformation on the –CH₂—CH₂– bond adjacent to the N atom. The mean plane of this pyrrolidine ring forms dihedral angles of 25.3 (3) and 32.1 (3)° with the two nitro­phenol rings. An intra­molecular N—H...O hydrogen bond occurs in the pyrrolidinium-2-carboxyl­ate mol­ecule. In the crystal, mol­ecules are linked via O—H...O and N—H...O hydrogen bonds, enclosing R³₂(8) ring motifs, forming chains running parallel to the a axis. These chains are further cross-linked by O—H...O and C—H...O hydrogen bonds, forming undulating two-dimensional networks lying parallel to (001).