The reaction between aryl aldehydes, the macrocyclic ligand 6-methyl-1,4,8,11-tetraazacyclotetradecane-6-amine (L-1), and NaBH3CN produces the corresponding benzyl-substituted ligands in good yield. Copper(II) complexes of the ligands derived from salicylaldehyde (L-2), p-hydroxybenzaldehyde (L-4), and p-carboxybenzaldehyde (L-5) were structurally characterized: [CuL2](ClO4)(2). 3H(2)O (monoclinic, P2(1)/c, a = 11.915(6) Angstrom, b = 13.861(2) Angstrom, c = 17.065(8) Angstrom, beta = 102.14(2)degrees, Z = 4); [CuL4](ClO4)(2) (monoclinic, P2(1)/n, a = 9.550(3) Angstrom, b = 17.977(2) Angstrom, c = 14.612(4) Angstrom, beta 96.76(1)degrees, Z = 4), and [CuL4](ClO4)(2) (monoclinic, P2(1)/n, a = 9.286(2) Angstrom, b = 11.294(1) Angstrom, c = 23.609(8) Angstrom, beta 93.68(1)degrees, Z = 4). Conjugation of several Cu-II complexes to a protein (bovine serum albumin) has been pursued with a view to the application of these macrocycles as bifunctional chelating agents in radioimmunotherapy.