Luminescent copper (I) complexes are considered as potential alternative for more widely used iridium, platinum nd ruthenium complexes. Cu(I) complexes typically shows photoluminescence via thermally activated delayed fluorescence (TADF) due to small energy gap between the S1 and T1 states and/or phosphorescence induced by large spin orbit coupling. we performed Time Dependent-DFT calculations for the newly synthesized class of triaminoborane-bridged diphosphine ligands (derived from 1,8,10,9-triazaboradecalin (TBD) called TBDPhos) TBDPhosCuX (X=Cl for 1, NPh2 for 2). Experiment have shown that post-synthetic modification of 1 with cooperative ligand can shift the solid-state emission. To understand the difference in luminescent properties of these complexes, TD-DFT calculations were performed. All the complexes geometries were optimized both in gas phase and in solvent using Density Functional theory with cam-b3lyp functional and def2tzvp basis set. TD-DFT studies were performed to obtain UV-vis absorption spectra in toluene and dichloromethane as solvent. Results suggested that for both complex 1 and 2 the dominant excitations in absorption spectra involves similar set of orbitals. HOMO-LUMO gap changes slightly (
