Three terbium coordination complexes have been synthesized. Bright green emission from these compounds can be obtained under infrared pulsed laser pumping. The detail photophysics demonstrates it is due to two-photon absorption of the ligand. In addition, the effect of different ligands on upconversion efficiency was compared and discussed. This study demonstrates that enhanced two-photon induced lanthanide emission can be achieved when it is sensitized with suitable organic ligands. The estimated upconversion efficiency was 1% with an excitation energy of 1.2 W/cm(2) under nanosecond pulse excitation, suggesting their potential applications in two-photon area. (C) 2004 Elsevier B.V. All rights reserved.