A simple dimer model is used to study the effect of quasi-degeneracy of the eigenstates of CT parentage on their electro-absorption (EA) spectrum. Typical approximations used in the interpretation of EA spectra are critically examined. The results confirm the former expectation that pairs of quasi-degenerate states endowed with no permanent dipole moment may give rise to second-derivative EA signals. The width of the CT transitions is found to set the scale according to which the CT levels should be classified as quasi-degenerate or not.