In this study, heteroleptic ruthenium complex Ru(dcbpy)(quqo)(NCS)(2) (dcbpy = 4,4-dicarboxy-2,2-bipyridine) where the quqo was 2-(2-quniolinyl)quinoxaline, was designed and studied theoretically. To gain insight into their structural, electronic and optical properties using DFT calculations were performed on Ru(dcbpy)(quqo)(NCS)(2) derived from the N3 dye. Molecular orbitals analysis confirmed that HOMOs of Ru(dcbpy)(quqo)(NCS)(2) are localized over the NCS ligand orbitals and the LUMO is localized over the quqo moiety. For N3, HOMOs are localized over the NCS moiety, however LUMO is localized over the dcbpy moiety. The TDDFT calculations showed that the new heteroleptic complex had more panchromatic absorption spectra in the region above 600nm compared to N3 dye. Absorption bands around 600nm are due to the conjugated length of quqo ligand.