Intermolecular energy transfer between Tb(thd)₃ and Eu(thd)₃ chelates (thd = 2,2,6,6-tetra-methyl-3,5-heptanedione) in a variety of solvents at room temperature is studied by both emission life-time and steady-state emission intensity techniques. Thirteen different solvents were examined, ranging from strongly coordinating dimethylsulphoxide (dmso) and dimethylformamide (dmf) to very weakly coordinating carbon tetrachloride (CCl₄) and chloroform (CHCl₃). Quenching of Tb(thd)₃ emission by Eu(thd)₃ was observed in all solvents except dmso, dmf and pyridine. Comparison of Stern–Volmer quenching constants obtained from lifetime measurements (K^τ_sv) versus intensity measurements (K^ϕ_sv) indicates a dominant dynamical quenching mechanism; no evidence is found for the formation of (mixed) dimeric species involving the Tb(thd)₃ and Eu(thd)₃ chelate systems. Bimolecular quenching rate constants, Stern–Volmer quenching constants, and emission lifetime data are reported for each of the solvents in which Tb(thd)₃ emission and Tb(thd)₃→ Eu(thd)₃ energy transfer were observed.