(K0.45Na0.55)NbO3-0.5 mol% K 4CuNb8O23 [KNN-KCN] solid solution was synthesized and its shear mode dielectric and piezoelectric properties were characterized as a function of temperature. The doped KNN material was found to possess comparable electric resistivity, piezoelectric, and electromechanical properties with pure KNN, but with a much higher mechanical Qm value, being on the order of 1500. The dielectric permittivity K11T and piezoelectric coefficients d15 for KNN-KCN were found to increase with the increasing temperature, while the electromechanical coupling factors k15 maintain a similar value till the phase transition temperature (To-t���200��C), above which, the properties drop significantly due to depolarization. The good temperature-dependent properties, together with its high mechanical Q m, demonstrate a practical potential of KNN-KCN materials for high power shear-mode applications. �� 2010 The American Ceramic Society.