In this work, two novel well-defined Cu (I) complexes of a Schiff base ligand are described. For this purpose, N, N '-bis (trans-cinnamaldehyde) ethylenediimine [C20H20N2] (L) and Cu (I) complex of the type [CuC20H20N2)PPh3Cl] (C1) and [Cu(C20H20N2)PPh3Br] (C2) were synthesised. IR, NMR, XRD and TGA analyses were used to characterise these compounds and single-crystal X-ray crystallography confirmed the structure of the compounds. The catalytic activity of the synthesised complexes was studied in azide-alkyne click reaction (AAC) and the best reaction condition was 15 mol% catalyst, 30 min and 45 degrees C in water, which can be considered moderate catalytic activity for the complexes. Material Studio 2017 software was used to obtain the geometry, energy, HOMO and LUMO of all structures by the quantum calculations (module DMol(3) and LDA/PWC). The computational results showed catalyst C2 has more reactivity than catalyst C1, and the C1-catalysed products form faster than the C2-catalysed products exceptions 4a and 4b. Product 4b (resulting catalyst C2) is formed faster than product (4a).