Abstract Solid solutions with a perovskite structure are formed in the PbTiO3-La(Me2/3Nb1/3)O3 (Me:Mg,Zn) systems up to about 70 mol% of La(Me2Nb1/3)O3. Structural, dielectric, electromechanical and dilatational properties of the ceramics have been measured as functions of composition and temperature. The electromechanical coupling constants kp and kt at room temperature are 28% and 68%, respectively, in the composition near 10 mol% of La(Mg2/3Nb1/3)O3. The temperature coefficient of the radial mode resonance frequency less than I ppmK−1 is obtained in the vicinity of 10 mol% of La(Me2/3Nb1/3)O3 with a small amount of MnO2 additive.