The orientation-dependent electromechanical properties were calculated for tetragonal Pb(In1/2Nb1/2)O-3-Pb(Mg1/3Nb2/3)O-3- PbTiO3 (PIN-PMN-PT) crystals based on single-domain data. The maximum electromechanical coupling k(33)* was found to lie along the polar direction [001], whereas the maximum piezoelectric coefficient d(33)* was 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 d(33) and coupling k(33) of [011] poled crystals were found to be on the order of 1000 pC/N and 0.75, respectively. The high d(33) of [011] poled crystals was associated with the high shear coefficient d(15) (similar to 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 d(33) and coupling k(33) of [011] poled crystals were found to decrease with increasing temperature.