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 stable 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. (C) 2010 Published by Elsevier B.V.