The orientation-dependent electromechanical properties were calculated for tetragonal Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3– PbTiO3 (PIN–PMN–PT) crystals based on single-domain data. The maximum electromechanical couplingwas found to lie along the polar direction [001], whereas the maximum piezoelectric coefficientwas found to occur along [011]. Subsequently, the piezoelectric properties of [011] poled tetragonal PIN–PMN–PT crystals, with an engineered domain configuration (“2T”), were studied using resonance impedance measurement and strain versus electric field (S–E) behavior, where the piezoelectric coefficient d33 and coupling k33 of [011] poled crystals were found to be on the order of 1000 pC/N and 0.75, respectively. The high d33 of [011] poled crystals was associated with the high shear coefficient d15 (∼2300 pC/N) in single domain state. Finally, the piezoelectric and electromechanical properties of [011] domain engineered tetragonal PIN–PMN–PT crystals were investigated as a function of temperature. In contrast to [001] single-domain PIN–PMN–PT crystals, the piezoelectric coefficient d33 and coupling k33 of [011] poled crystals were found to decrease with increasing temperature.