The crystal and molecular structure of two salts, I and III, and one molecular complex, II, formed by combining 1,1'-binaphthyl-2,2'-dicarboxylic acid (BNDA) with pyrazole (3) and 3,5-dimethylpyrazole (4) has been determined by X-ray crystallography. The most striking feature is the spontaneous resolution of the racemic BNDA host by co-crystallization with 4, an achiral guest, to form the salt III. The absolute configuration of three manually selected crystals of In have been established by crystallographic methods. The two crystals formed by the (P)-enantiomer display a negative Cotton effect. C-13-CPMAS-NMR Spectroscopy has been used to compare the compounds obtained by crystallization with those prepared by mechanical grinding.