Tetraazamacrocycles containing the pyridine moiety as part of the cyclic backbone and acetate pendant arms were prepared. The resulting products were characterized by high resolution NMR (H-1 and C-13) spectroscopy and single-crystal X-ray diffraction. Single-crystal X-ray diffraction data were obtained for the following compounds : py[12]aneN4 . HCl, C11H19N4Cl, orthorhombic Pnma (No. 62), a = 10.304(6) Angstrom, b = 9,160(2) Angstrom, c = 13.552(2) degrees, Z = 4, Mo K alpha, lambda = 0.710 69, R = 0.037, R(w) = 0.036; and BP2A . 2HCl . 3H(2)O, C18H22NO4Cl(2) . 3H(2)O, triclinic P (1) over bar (No. 2), a = 10.201(0) Angstrom, b = 13.267(3) Angstrom, c 8.612(6) alpha = 97.676(2)degrees, beta = 105.821(0)degrees, lambda = 86.363(7)degrees, Z = 2, Mo K alpha, lambda = 0.710 69, R = 0.039, R(w) = 0.038. In addition, protonation constants (log KHnL) and metal ion stability constants (log K-ML) for BP2A (log K-H1-4L = 9.57, 5.99, 2.59, 2.22; log K-MgL = 8.9; log K-CaL = 10 0; log K-GdL = 14.5) and PC2A (log K-H1-5L = 12.5, 5.75, 3.28, 2.38, similar to 1; log K-MgL = 8.4, log K-CaL = 10.0, log K-GdL = 16.6) were determined using potentiometric and NMR pH titrations. These values agree well with previously reported literature values for analogous ligand systems.