The [111]-oriented rhombohedral Mn-doped 0.15Pb(In1/2Nb1/2)-0.55Pb(Mg1/3Nb2/3)O-3-0.30PbTiO(3) (Mn:PIMNT(15/55/30)) crystal and the [001]-oriented tetragonal Mn-doped 0.29Pb(In1/2Nb1/2)-0.29Pb(Mg1/3Nb2/3)O-3-0.42PbTiO(3) (Mn:PIMNT(29/29/42)) crystal were poled under different conditions. The pyroelectric performance of the two crystals as a function of poling temperature, as well as the relationship with ferroelectric domain configuration and phase structure was investigated systematically. The pyroelectric properties of the two crystals enhance with rising the poling temperature, which can be attributed to the improvement of the single state. And for the rhombohedral Mn:PIMNT(15/55/30) crystal locating near morphotropic phase boundary (MPB), the increase of tetragonal phase induces the deterioration of pyroelectric properties. Due to more residual tetragonal phase, the pyroelectric coefficient of the Mn:PIMNT(15/55/30) crystal poled at 150 degrees C is lower than that poled at 100 degrees C. In general, both the crystals poled above T-C achieve nearly single state, exhibiting the best pyroelectric properties with relatively high Curie temperature (T-C), where P = 9.71 x 10(-4) C m(-2) K-1, F-i = 3.88 x 10(-10) m V-1, F-v = 0.068 m(2) C-1 and F-d = 29.7 x 10(-5) Pa-1/2 for the rhombohedral Mn:PIMNT(15/55/30) crystal (T-C = 171 degrees C) and P = 6.78 x 10(-4) C m(-2) K-1, F-i = 2.71 x10(-10) mV(-1), F-v = 0.1 m(2) C-1, F-d = 23.54 x 10(-5 )Pa(-1/2) for the tetragonal Mn:PIMNT(29/29/42) single crystal (T-C = 251 degrees C), meeting the stable operation of infrared detector at relatively high environmental temperatures.