Heteroleptic Zn (II) complexes containing 8-hydroxy quinoline as preliminary ligand and pyrazolone based derivatives as secondary ligand were synthesized and their structures confirmed by NMR, Mass, FT-IR, UV-vis and Elemental analysis. Theses complexes show good photoluminescence properties in solid and solution state in the range of 505-544 nm with quantum yield 0.38 to 0.50. Whereas these complexes also show good life time in the range of 0.037 to 0.043 ms. These complexes show shift in the range of 25-30 nm. in different polar and nonpolar solvents due to intramolecular charge transfer (ICT). The bandgap of these complexes is around ~2.60 eV. Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of all complexes are determine by cyclic voltammetry it obtained in the range of and ~ (-5.29 eV) and ~(-2.69 eV). The energy band gap, frontier molecular orbitals (FMO) energy levels and geometrical structures were optimized using density functional theory (DFT) with B3LYP/6-31G* basic set on Spartan'18 software. All complexes displayed high thermal stability. Graphical Abstract Donor-Bridge- Accepter (D-B-A) based Heteroleptic Zn(II) complexes for OLEDs application.