The reaction between alkyl or aryl aldehydes and macrocyclic ligands with pendant amine groups produced imidazolidine-containing bi- or tricyclic ligands. The copper complexes of three of these ligands were structurally characterized: [(CuLCl)-Cl-3]. 3H(2)O (triclinic, P (1) over bar, a 10.041(2) Angstrom, b = 10.172(1) Angstrom, c = 11.202(1) Angstrom, alpha = 92.07(1)degrees, beta = 96.76(2)degrees, gamma = 92.99(1)degrees, Z = 2), [Cu(H2L4)Cl]Cl . 2H(2)O (monoclinic, P2(1)/n, a = 15.159(5) Angstrom, b = 10.645(1) Angstrom, c = 19.094(6) Angstrom, beta = 93.78(1)degrees, Z = 4), [CuL5]. 2H(2)O . NaNO3 (monoclinic, P2(1)/n, a = 10.649(8) Angstrom, b = 7.261(2) Angstrom, c = 15.25(1) Angstrom, beta = 94.77(4)degrees, Z = 2). The conformational rigidity and stereochemical activity of these macrocycles and their complexes are discussed in comparison with close analogues.