The molecular structures in solutions were predicted for a chiral copper(II) complex [Cu(R-mben)₂]²⁺ [R-mben = N-(methylbenzyl)ethylenediamine] based on the circular dichroism (CD) spectra in an acetonitrile solution and a pyridine solution. Each CD spectrum was analyzed to obtain the spectral components, and the coordination geometry around the copper(II) ion was estimated to be square-pyramidal on the basis of the observed spectral components. The structures of twelve probable conformers were optimized by DFT computation, and the CD spectrum was predicted for each structure by the TD-DFT method. Then, comparing the observed CD data with the predicted CD data, the structures in solutions were estimated.