For electronic applications it is profitable to induce spin transitions by applying an electric field and to facilitate thereby the construction of molecule-based devices for which the magnetic state can be controlled electrically. This effect represents an important advance in molecular spintronics and a basis for magnetic molecule-based quantum computing. The possibility to manipulate directly by the magnetic properties with the aid of the electric ones can be provided by mixed valence (MV) clusters. In these clusters the value of the Stark splitting or shift of levels in the dc electric field is expected to exceed significantly that for an isolated atom since the cluster dipole moment is proportional to the dimension of the cluster. The ability of MV clusters to acquire a dipole moment in the external electric field causes interesting peculiarities in their polarizability and magnetic characteristics. In the present paper we examine the effects of the electric dc field in the magnetic and polarizability characteristics of trimeric MV clusters. In order to elucidate the main peculiarities the most simple trinuclear MV clusters Cu(II) Cu(II) Cu(III) with the electronic configuration d9 d9 d8 are examined. The spectrum of low-lying states of these clusters consists of two exchange levels split by the ―extra‖ hole tunneling into orbital singlets 1, 3 A 2 1A and doublets 3E, 1E . The external electric field that lies in the plane of the triangle formed by the cluster ions is shown to produce considerable effects. Removing the degeneracy of the 2S 1E levels and mixing the states belonging to the same full spin value S this field facilitates the trapping of the ―extra‖ hole and lowers the energy of the ground state. The decrease in energy depends on the magnitude and direction of the electric field. For certain parameter values spin crossovers induced by the applied field are possible. The lowtemperature limit of the magnetic moment defined by the spin of the ground state can be changed by the external electric field. So the strong coupling of the MV cluster with the electric field provides an unique opportunity of governing by the cluster magnetic properties through the field. The most noticeable effects in the magnetic behavior of the cluster are attainable at low temperatures, when only the ground state is populated. Polarizability effects induced by the external electric field are also examined. In the delocalized A and E states the mean value of the cluster dipole moment vanishes. In the states with fixed valence clusters possess dipole moments. The electric field promotes a transition between these states. By playing with the magnitude and the direction of the applied field different types of the temperature dependence of the cluster mean dipole moment can be obtained. When the ground state of the cluster is an 2S 1E state even weak applied electric fields produce significant dipole moments. In the case of a singlet ground state weak applied fields lead to small mean dipole moments. With field increase the cluster ground state changes from an A state to an E - state, and the dipole moment undergoes a low-temperature jump. Besides the described effects the most important impact of the external electric field is the predicted anisotropy of polarizability caused by this field. The low temperature limit of the mean dipole moment as a function of the direction of the external dc electric field (Fig.1) shows that the most pronounced effect is produced by the fields oriented towards the vertexes of the triangle formed by the cluster ions.