Excitation and emission spectra and luminescence lifetimes of Eu³⁺ complexes obtained by dissolving anhydrous EuCl3 and EuCl3/2,2-bis(hydroxymethyl)-2,2â ²,2â ³-nitrilotriethanol (Bis-tris) in anhydrous dimethylformamide (DMFâ ) and those from a Eu(Bis-tris)2Cl3 crystalline sample have been studied. Two distinct Eu³⁺ complexes were observed when anhydrous EuCl3 was dissolved in anhydrous DMF, and one was interpreted as an outer-sphere complex of Cl^â anion. Dissolution of an excess amount of vacuum dried NaClO4 or KPF6 in anhydrous DMF resulted in longer luminescence lifetimes, presumably reducing the effects of trace amounts of water in the solvent due to competitive binding of the water in the solvent by alkali metal cations. The quenching rate constant for the ⁵D0 state of Eu³⁺ ion by each complexed DMF molecule in solution and by each OH group in the Bis-tris from the Eu(Bis-tris)2Cl3 crystalline sample were 54â ±â 1 and 495â ±â 5 s^{â 1}, respectively, and these were used to interpret the plausible structures of the different Eu³⁺ complexes in the EuCl3/Bis-tris/DMF solution.