a b s t r a c t The vibronic coupling theory is applied to study the absorption and circular dichroism (CD) spectra of bis-1,8-naphthalimide molecule considered as a dimer with 1,8-naphthalimide (NDI) chromophores. The sta-ble configuration of that dimer was found with a help of density functional B3LYP/cc-pVDZ approach. The results of conformational analysis and the vibronic parameters derived from B3LYP/aug-cc-pVDZ and PBE0/aug-cc-pVDZ computations have led to the CD and absorption spectra, which are in very good agreement with the experimental spectra observed for the excitation energy corresponding to 1A 1 ? 2A 1 and 1A 1 ? 1B 1 overlapping transitions in the chromophore. Ó 2010 Published by Elsevier B.V.