Macrocycle 2 was synthesized via precursor 9 by the condensation of bishydrazide 10 40 with phthalaldehyde 11 in the presence of TBAH2PO4 in 57% yield (Scheme 2). The H2PO4 -template proved to be essential since, when absent, the macrocycle was obtained as a mixture with larger macrocycles and oligomers which could not be separated, whereas the presence of TBAH2PO4 caused the desired macrocycle to selectively precipitate from solution.