For several double-helical molecules, the dependence of electronic circular dichroism (ECD) spectra on the molecular and electronic structures is investigated on the basis of TDDFT computations with the B3LYP hybrid functional. The calculations of a model molecule reveal that an acute-angled rotational dihedral angle other than an obtuse-angled rotational dihedral angle between two naphthyls implies Davydov splitting of exciton coupling. For the R enantiomers, the acute-angled rotational dihedral angle implies a negative lowest-energy Cotton effect, which is induced by electron density transfer from binaphthyls to phenyethynyls in the S0 → S4 excitations. Due to the large positive rotational strength of the S0 → S1 transition, the lowest-energy Cotton effect of the simplest cyclophane R-1 is positive, where the electron density transfer from phenyethynyls to binaphthyls plays an important role.