The 1:1 complex between the zwitterionic piperidinium-3-carboxylate (P3C) and salicylic acid (SAL), P3CÁSAL, has been characterized by single crystal X-ray analysis, FTIR and NMR spectroscopy, and by DFT calculations. The crystals are orthorhombic, space group Pbca, with a = 11.6477( 7), b = 9.1754(6), c = 23.5833(12) Å. An OAHÁ Á ÁO bridge (2.537(1) Å) links the SAL and P3C moieties. The proton in this H bond is located closer to the salicylic carboxylate group. In the P3C moiety, the piperidine ring adopts the chair conformation, and the carboxylate group is in the axial orientation and is stabilized by an intramolecular N + AHÁ Á ÁO hydrogen bond of 2.847(1) Å. In the crystal packing, two P3CÁSAL units form a centrosymmetric dimer through a pair of intermolecular N + AHÁ Á ÁO bonds of 2.801(1) Å. The dimers form a zigzag chain linked via another N + AHÁ Á ÁO bond (2.799(1) Å). In the structures of the monomeric [P3CÁSAL] and dimeric [(P3CÁSAL) 2 ] species optimized by B3LYP/6-31G(d,p) calculations, both the interand intra-molecular hydrogen bonds are shorter than in the crystal. The FTIR spectrum shows a broad absorption in the 3100-2400 cm À1 region attributed to mNH and mOH vibrations. The broad absorption in the 1500-600 cm À1 region is attributed to the OAHÁO hydrogen bonds. The 1 H and 13 C NMR spectra have been analyzed to elucidate the structure of the P3CÁSAL complex in solution. The GIAO magnetic isotropic shielding tensors have been used to predict the 1 H and 13 C chemical shifts in DMSO solution.