A polyoxapolyaza heteroditopic macrobicyclic compound (btpN₄O₃) was synthesized. The acid–base behaviour of the compound as well as its binding ability for zwitterionic amino acids were studied by potentiometry at 298.2 ± 0.1 K in H₂O–MeOH (50 : 50 v/v) and at I = 0.10 ± 0.01 M in NMe₄TsO. The H_nbtpN₄O₃ⁿ⁺ showed preference for amino acids containing tetrahedral anionic groups.