The complete perovskite solid solutions of(1-x)Pb(Mg1/3Nb2/3)O-3 (PMN)-xPb(In1/2Nb1/2)O-3(PIN), where x = 0.1-0.9; were synthesized from the solid state reaction of columbite (MgNb2O6), wolframite (InNbO4) and PbO mixture and their dielectric propel ties and microstructures were investigated. Pure perovskite phase was obtained by the incorporation of PMN into PIN and an increase in PIN resulted in a linear increase in the lattice parameter and a gradual decrease in the grain size. With increasing x, the maximum permittivity (epsilon(rm)'), decreased and the temperature T-m, where epsilon(rm)' appeared, shifted towards a higher temperature showing the presence of relaxer ferroelectricity.