A systematic estimation of aromaticity in squaramide complexes with anions has been studied using structural and magnetic criteria. Results based on Nucleus Independent Chemical Shift (NICS) predict that squaramide is less aromatic than its complexes with several anions. We had previously observed the same behavior in squaramide complexes with cations. This bifunctionality can be used to design ditopic receptors. In fact a 1: 1: 1 complex between squaramide and both ammonium cation and formiate anion is more aromatic than any of the other two 1:1 squaramide-cation/ anion complexes. (C) 2002 Elsevier Science B.V. All rights reserved.