Combinatorial chemistry was introduced into the field of artificial channels first by us in 2017 to evolve synthetic potassium channels with high K+/Na+ selectivity of 9.8 (J. Am. Chem. Soc. 2017, 139, 12338). There is still much to do with this combinatorial chemistry. Some of its already demonstrated yet unpublished applications include increase of K+/Na+ selectivity to 20.1 and development of amino acid-specific transporters. Along the same line, we would be interested to further increase K+/Na+ selectivity or investigate if Na+/K+ selectivity can reach an unprecedented value of 10.