A novel azopyrimidin ligand N-(1-(4-aminophenyl)ethylidene)-4-(2-amino-3-(4-methoxyphenyl)diazenyl)[1,5- a]pyrimidin-7-yl)benzeneamine. The prepared azo-ligand was used for further complexes formation reaction with different metal ions using Ni(II)(CH3COO)2, Cu(II)(CH3COO)2, Pd(II)Cl2, Ag(I)NO3, Pt(IV)Cl4 and HAu(III)Cl4 by a molar ratio of ligand : metals. The stereochemistry and the mode of bonding of the complexes were achieved based on elemental analysis, IR, UV-Vis, 1HNMR and MS as well as thermo-gravimetric analysis (TGA). Structures proposed for geometry of the chelates based on their electronic spectra and magnetic moment. The metal complexes possessed an tetrahedral for [Ni(II) and Cu(II)], square planer for [Pd(II), Pt(IV) and Au(III)] and a triagonal geometry for Ag(I). The solid complexes have been synthesized and studied by TGA analysis. The thermal dehydration and decomposition of these complexes were studied kinetically using the integral method applying the Coats–Redfern and Horowitz Metzeger equation. The band gap energy values of all compounds are characteristic of semiconductor materials. The metal complexes show inhibitory activity against breast carcinoma cells.