Cyclometalated ruthenium dyes improve significantly the performance of dye sensitized solar cells (DSSCs) based on conventional ruthenium dyes. Here, this study examined four thiocyanate-free cyclometalated ruthenium dyes using the density functional theory (DFT). The geometrical, electronic structural, and photophysical propertiesof the dyes and the dyes tethered to a TiO2 surface were examined in both the presence and absence of an acetonitrile solvent. The Kohn-Sham eigenvalues of the molecular orbitals of the dyes were destabilized by ca. 2 eV in the presence of the solvent. The absorption peaks did not change significantly in position but hyper chromic shifts of more than two-fold occurred. When adsorbed on a TiO2 surface, the dyes showed redshifted absorption of approximately 20 nm. To the best of our knowledge, a systematic and comprehensive first-principles investigation on cyclometalated ruthenium dyes in vacuum, solvent, and tethered to TiO2 has been carried out for the first time.