After adding 1.0 mM of metal ion into cyanidin solution, the CyCu(II) complex shows longer wavelength from 570 nm to
590 nm as the same result as complexation of Cy-Pb(II) shifting from 560 nm to 580 nm. For Cy-Fe(III) complex, the bathochromic shift also presents from 540 nm to 560 nm. The formation of Cy and Al(III) shows the wavelength shift from 550 nm to 570 nm.