A diboronic acid saccharide (covalent) receptor site and a crown metal ion (electrostatic) receptor site are successfully coupled in an allosteric system. The binding of monosaccharides with 2b as intramolecular 1:1 complexes was monitored by circular dichroism (CD). Added calcium perchlorate reduces the binding of the 1:1 saccharide complexes as followed by a decrease in the CD activity. This is a novel allosteric system which mimics the action of the Na+/D-glucose cotransport protein in nature.