A theoretical approach for the luminescence thermal quenching through ligand-to-metal charge transfer (LMCT) states in lanthanide compounds is developed. Considering single configurational coordinate models for both LMCT and intra-ligand states, expressions for the spectral overlap integrals involving a donor state, 4f-state (case 1) or an intra-ligand state (case 2), and the LMCT, were obtained. Comparison between theoretical and experimental results of quantum efficiencies for some coordination compounds is quite satisfactory. (c) 2006 Elsevier B.V. All rights reserved.