Display omitted •Monometallic heteroleptic complexes of Dy(III) with general formula Dy(Hfodo)3L have been synthesized.•The prepared complexes have been investigated by thermal, spectroscopical and electrochemical studies.•Electronic and optical band gap has found to be quite similar and in the range of conducting region.•Yellow luminescence is observed corresponding to 4F9/2→6H13/2 transition which demonstrates the utility of complexes in generation of high-efficiency organic light emitting materials. A series of ternary complexes of dysprosium tris-β-diketonate was prepared by using phenanthroline and its substituted derivatives as neutral ligands. The complex formation or the coordination mode of organic moieties was analysed by elemental, infrared, proton NMR and UV–Visible analyses. The anhydrous nature of prepared complexes was illustrated by using thermogravimetric and infrared studies. The band gap was also measured which is present in the range of conducting zone. The luminescence characteristics were measured in solid and solution. The complex upon excitation under UV light generates emission in the yellow region which indicates proficient energy transference from coordinated moieties to the central Dy(III) ion. The correlated color temperature (CCT) of Dy(III) complexes has been calculated and found to be ∼ 5000 K which belongs to a cold light region. The contribution of 4F9/2 → 6H13/2 transition (75 %) is highest towards total radiative processes and it might be regarded as an acceptable transition for laser amplification. The prepared complexes of Dy(III) could be utilized in fabricating OLEDs and displays due to their band gap value, large thermal stability and high luminous characteristics.