Two novel complexes of Sm(III) and Dy(III) with mixed oxydiacetate (ODA) and 1,10-phenanthroline (phen) ligands were synthesized and their structure and luminescence properties were characterized. The complexes of [Ln(ODA)(phen)·4H 2 O]Cl·5H 2 O [Ln=Sm and Dy] crystallize in the monoclinic space group P2 1 /n with Sm: a=12.3401(14)Å, b=16.821(2), c=12.6847(11)Å, β=107.939(10)°, V=2505.0(5)Å 3 , Z=4 and ρ=1.841mg/m 3 , and with Dy: a=12.289(7)Å, b=16.805(6)Å, c=12.705(4)Å, β=108.144(18)°, V=2493.4(19)Å 3 , Z=4 and ρ=1.786mg/m 3 . The complexes of [Sm(ODA)(phen)·4H 2 O] + and [Dy(ODA)(phen)·4H 2 O] + excited by UV light produce orange red and lightly white emissions, respectively, via the nonradiative energy transfer from phen to the metals. The quantum yield of the sensitized luminescence of [Dy(ODA)(phen)·4H 2 O] + (Q=19%) is much greater than that of [Sm(ODA)(phen)·4H 2 O] + (Q=1.4%). The luminescence decay times of the complexes were in a few microsecond range and independent of temperature.