Hydrogen-bonded co-crystal structure of benzoic acid and zwitterionic l-proline

The title compound [systematic name: benzoic acid–pyrrolidin-1-ium-2-carboxyl­ate (1/1)], C(7)H(6)O(2)·C(5)H(9)NO(2), is an example of the application of non-centrosymmetric co-crystallization for the growth of a crystal containing a typically centrosymmetric component in a chiral space group. It co-crystallizes in the space group P2(1)2(1)2(1) and contains benzoic acid and l-proline in equal proportions. The crystal structure exhibits chains of l-proline zwitterions capped by benzoic acid mol­ecules which form a C(5)[R (3) (3)(11)] hydrogen-bonded network along [100]. The crystal structure is examined and compared to that of a similar co-crystal containing l-proline zwitterions and 4-amino­benzoic acid.