On the basis of Li-7 NMR experiments, the complex-formation reaction between Li+ and the tridentate N-donor ligand terpyridine was studied in the ionic liquids [emim][NTf2] and [emim][ClO4] as solvents. For both ionic liquids, the NMR data implicate the formation of [Li(terpy)(2)](+). Density functional theory calculations show that partial coordination of terpyridine involving the coordination of a solvent anion can be excluded. In contrast to the studies in solution, X-ray diffraction measurements led to completely different results. In the case of [emim] [NTf2], the polymeric lithium species [Li(terpy)(NTf2)] was found to control the stacking of this complex, whereas crystals grown from [emim][ClO4] exhibit the discrete dimeric species [Li(terpy)(ClO4)](2). However, both structures indicate that each lithium ion is formally coordinated by one terpy molecule and one solvent anion in the solid state, suggesting that charge neutralization and pi stacking mainly control the crystallization process.