The goal of the article is to collect and discuss spectral data for the dyads and reference molecules in the large spectral range, using various methods of investigations. We present information on change of configurations, electronic and vibrational properties of both parts of the dyads after their formation, and their possible relationship with electron transfer mechanism. From the conformational and spectral investigations, a strong correlation between the molecular structure of investigated species and their electronic as well as vibrational spectra arises. It testifies a significant redistribution of the charges upon the covalent linkage of a dyad.