The synthesis and characterization of the new tetraazamacrocycle 4-(N),10-(N)-bis[2-(3-hydroxy-2-oxo-2H-pyridin-1-yl)acetamido]-1,7-dimethyl-1,4,7,10-tetraazacyclododecane (L) is reported. L shows two 3-(hydroxy)-1-(carbonylmethylen)-2(1H)-pyridinone moieties as side-arms of a tetra-aza-macrocyclic base. The key coupling of side-arms was studied and the most significant results were obtained by activating the 3-(benzyloxy)-1-(carboxymethyl)-2(1H)-pyridinone as pentafluorophenol ester. The acid–base properties of L and its capability to interact with simple ammonium cations were investigated by potentiometric measurements in aqueous solution (298.1±0.1 K, I=0.15 mol dm−3). Protonated species of L can bind NH4+ or primary ammonium cations such as MeNH3+ discriminating them from secondary or tertiary ammonium cations such as Me2NH2+ or Me3NH+ which are not bound in aqueous solution.