Tris((2-pyridyl)methyl)amine forms complexes with sodium and lithium ions. The enthalpy of formation of the lithium iodide complex in deuterioacetone was found to be 8.0 +/- 0.3 kcal/mol from proton resonance spectroscopic determination of exchange rates as a function of temperature. The complex crystallizes in the monoclinic space group P2(1)/c with a = 13.077(4) Angstrom, b = 12.221(11) Angstrom, c = 26.613(7) Angstrom, and beta = 94.642(24)degrees, with Z = 4;and R(w) = 0.083. Tris(2-(2-pyridyl)ethyl)amine forms a weaker complex with lithium ions but does not complex sodium ions. Theoretical calculations of the structure of the lithium complex were in good agreement with the results of the X-ray structure determination.