2:2 Complex of (R) and (S)-piperidine-3-carboxylic acids (P3C) with (2R,3R)-tartaric acid (TA), 1, has been characterized by single-crystal X-ray analysis, FTIR and NMR spectroscopies, and by DFT calculations. The crystals of 1 are monoclinic, space group P2 1 . The crystal structure is formed by two distinct P3CH + ·TA − components, A and B, linked by an O–H⋯O hydrogen bond of 2.603(2)Å. The A and B components differ in the absolute configuration of the C(3) atom of P3CH + ; (S) in A and (R) in B. The piperidinium-3-carboxylic acid and (2R,3R)-semi-tartrate anion moieties of the components A and B are linked by O–H⋯O hydrogen bonds of 2.517(1) and 2.535(1)Å, respectively. In A and B the piperidinium rings adopt the chair conformation with the carboxyl group in the equatorial position. The structures of the monomers of P3CH + ·TA − , 3A and 3B, as well as of a dimer 2, have been optimized by the B3LYP/6-31G(d,p) approach. The chemical shift assignments were based on two-dimensional 1 H– 1 H and 1 H– 13 C experiments.