A number of consecutive generations of bithiophenesilane dendrimers and their precursors are studied by the methods of the equilibrium electro-optical Kerr effect, dielectric polarization, and absorption spectroscopy in dilute toluene solutions. It is shown that the molecules of hybrid dendrimers containing bithiophene fragments covalently linked via silicon atoms are not kinetically rigid and feature the small-scale mechanism of interaction with external electric fields. A tris(bithiophene)methylsilane fragment is found to be the subunit responsible for the electro-optical and optical spectral properties of the above hybrid dendrimers. It is revealed that the polarization of bithiophensilane dendrimers predominantly shows the deformation pattern.