The phase-formation processes in the Bi2O3-M2O3-V2O5 (M = Y, In) systems were investigated. The associated sequence of phase transformations and the conditions for the preparation of phase-pure Bi4V2 − 2x M2x O11 − 2x solid solutions were established. The lattice parameters of the solid solutions were determined, and their conductivity was measured as a function of temperature and composition.