The interaction of PdCl4(2-) with the macrocyclic ligands of the series [3k]aneN(k) has been studied both in solution and in the solid state. [18]aneN6 and [21]aneN7 form both mono- and binuclear Pd2+ complexes, whose stability constants have been determined in 0.5 mol dm-3 NaCl at 298.15 K. [21]aneN7 also forms, in solution, a trinuclear species in which an amino group deprotonates to bridge two Pd2+ ions, as observed in the solid state. The crystal structure of the complexes [Pd2([18]aneN6)Cl2][ClO4]2 and [Pd3([21]aneN7)Cl3][ClO4]2.H2O have been solved by single crystal X-ray analysis. C12H30N6Cl4O8Pd2: monoclinic, space group C2/m, a = 10.876(2), b = 18.117(2), c = 7.043(2) angstrom, beta = 113.78(2)-degrees, V = 1270(12) angstrom 3, Z = 2, D(calc) = 1.92 g cm-3, mu = 16.94 cm-1. R = 0.063, R(w) = 0.059. C14H36N7Cl5O9Pd3: orthorhombic, space group Pcab, a = 13.125(7), b = 13.213(3), c = 33.570(5) angstrom, V = 5822(3) angstrom 3, Z = 8, D(calc) = 2.15 g cm-3, mu = 21.20 cm-1. R = 0.074, R(w) = 0.061. In very acidic solutions the polyammonium cations (H(k)[3k]aneN(k))k+ interact with PdCl4(2-) forming second sphere coordinated species. These reactions have been followed by a microcalorimetric technique in 2 mol dm-3 HCl solutions. The slowness of the reactions of (H10[30]aneN10)10+ with PdCl4(2-) has been interpreted in terms of inclusion of the anion into the receptor's cavity as shown by the crystal structure of [(PdCl4)(H10[30]aneN10)][PdCl4]2Cl4: triclinic, space group P1BAR, a = 7.760(3), b = 11.448(4), c = 13.399(11) angstrom, alpha = 96.31(8)-degrees, beta = 104.50(6)-degrees, gamma = 92.30(3)-degrees, Z = 1. R = 0.0 and R(w) = 0.039.