This paper presents the synthesis of several complexes of Ln (III) (Ln: Tb, Dy, Yb) with mixed ligands (benzo c and 2,2’-dipyridine-N-oxide). They are represented by the general formula of Ln(Benz)2(DipyO)(H2O)2 (Ln: Tb, Dy, Yb
Benz-: Benzoate, D p O: 2,2’-dipyridine-N-oxide). The characterization of these complexes has been studied by IR, thermal analysis, mass, and emission spectroscopy approaches. The results from IR spectroscopy suggested that complexes had been synthesized successfully, and the coordination modes of the ligands to Ln(III) centres had been investigated by IR spectroscopy. Mass spectroscopy findings showed that the synthesized complexes were monomers and that they are stable. In addition, thermal analysis indicates that they are all quite stable to heat. The emission spectra of the Tb(Benz)2(DipyO)(H2O)2 displayed three bands arising from the 5D4 → 7F5 dominant transition located at 545 nm, the weaker 5D4 → 7F6, 5D4 → 7F4 transitions located at 490 and 587 nm, respectively. The emission spectra of the Yb(Benz)2(DipyO)(H2O)2 displayed one band at 452 nm, meaning the 2F5/2→2I7/2 energy level of Yb3+ was observed. The results of our study demonstratedthat these complexes exhibited room-temperature photoluminescence.