Pyrrolidinium-2-carboxyl-ate-4-nitro-phenol (1/2)

In the title compound, C5H9NO2·2C6H5NO3, the pyrrolidine ring of the pyrrolidinium-2-carboxyl-ate 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 nitro-phenol rings. An intra-molecular N-H⋯O hydrogen bond occurs in the pyrrolidinium-2-carboxyl-ate mol-ecule. In the crystal, mol-ecules are linked via O-H⋯O and N-H⋯O hydrogen bonds, enclosing R (3) 2(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).