related europiumcomplexes Eu(TTA)3PhoR and Eu(TTA)3BpoR were synthesized (HTTA = 2-thenoyltrifluoroacetone). Single crystal X-ray diffraction of Eu(TTA)3Php (Php = 2-(pyridyl)-1,10-phenanthroline) shows that Php acts as a tridentate N⁁N⁁N ligand, leading to a high stability of the complex for vacuum evaporation. When an oxadiazole moiety is incorporated into the ligand, the corresponding europium complexes