Six new macrocyclic complexes were synthesized by reaction of 1,4-bis(2-carboxyaldehyde phenoxy)butane with various diamines. Then, their nickel(II) perchlorate complexes were synthesized by the template effect by reaction of 1,4-bis(2-carboxyaldehyde phenoxy)butane, Ni(ClO 4 ) 2 AE 6H 2 O and various diamines. The metal-to-ligand ratio of Ni II metal complexes was found to be 1:1. The compounds are coordinated to the central metal as tetradentate O 2 N 2 ligands The Ni II complexes are proposed to exhibit tetrahedral geometry. Ni II metal complexes are 1:2 electrolytes as shown by their molar conductivities (K M ) in DMF (dimethyl formamide) at 10 )3 M. The structure of Ni II metal complexes is proposed from elemental analysis, f.t.-i.r., u.v.-vis., magnetic susceptibility measurements, molar conductivity measurements and mass spectra.