[en] The paper attempts to investigate the phase formation of a Zr- and Sn-substituted [(Na_0_._5Bi_0_._5)_0_._8_0Ba_0_._2_0](Ti_1_−_yB_y)O_3 system during its solid state synthesis. The synthesis was found to be a multi-step process associated with the formation of a number of intermediate phases which however depended on the compositions and sintering temperatures. Single phase solid solutions were obtained when the sintering temperature was increased to 1000 °C–1100 °C. Increase in the concentration of substituting ions, on the one hand, tends to linearly increase the crystal cell size whereas the tolerance factor, on the other hand, gets reduced bolstering the stability of anti-ferroelectric phase as compared to that of ferroelectric phase’. (paper)