Flavanol compounds are chalcone derivatives, generally found in hydroxy substituted forms that can act as ligands. Hydroxy-substituted flavonols are found in many plants but in very small amounts. In ... order to enrich and expand the use of this compound as a ligand, the synthetic methods were carried out through structural variations, one of which was by substitution using chloride and then the compound (2-(4-chlorophenyl)-3-hydroxy-4H-chromene-4-one) was obtained. In this research, the study was conducted using the compound (2-(4-chlorophenyl)-3-hydroxy-4H-chromene-4-one) as a ligand for complex formation with copper (II). From the results of the study, the mole ratio of the ligand with copper (II) metal was 2:1, pH 7.01 with a complex stability time of 15-25 minutes. The complex formed is bright yellow in color and soluble in chloroform. From the characterization of the resulted complex, it was appeared that Cu-flavonol chloride with UV-Vis spectrophotometer showed maximum absorption at wavelengths 273 and 429 indicating the presence of benzoyl and cinnamoyl peaks, with FT-IR showing the wave number 1545cm-1 indicating the presence of Cu=O-Cu bonds and absorption at 682 cm-1 indicating the presence of Cu-O bonds more