Electrical conductance measurements of lithium picrate and lithium perchlorate in isodielectric solvents (i.e. acetonitrile, methanol and N,N-dimethylformamide in the concentration range 10(-4) less-than-or-equal-to c/mol dm-3 less-than-or-equal-to 10(-2) are reported. The data analysed by the Fuoss three-parameter equation have shown that. in spite of the similarity of the macroscopic dielectric constants of the solvents, the ion pair association constants of both electrolytes strongly depend on the molecular details of ions and solvent molecules. The complexation of lithium ion by the 15-crown-5 (15C5) macrocyclic ligand in the above solvents has also been investigated. The results show that the presence of 15C5 increases the ionization of the electrolytes in relation to the solvation efficiency of the solvents. Such a result is of particular interest in view of the technological applications of lithium salt solutions.