The unwanted structural changes and isolated unoccupied states in the band structure of TiO2 due to doping could be minimized by proper selection of dopants. A good combination of dopants would improve the optical response in visible regime and remove the isolated states from the band gap while keeping minimum structural distortion. Enhanced visible light absorption and effective utilization of photo-generated carriers would improve the photoactivity of TiO2 under solar irradiations. Mono-doped, co-doped and tri-doped models of molybdenum (Mo), carbon (c), and nitrogen (N) are developed in the structure of anatase TiO2 and the corresponding change in the geometrical structure, band structure, and optical response is noted. The Mo and C co-doping produced least structure modification when compared to a reference TiO2 system. The Mo 3d states are mixed with Ti 3d states reducing the band gap of Mo-doped TiO2. While shifting the Fermi level to the middle of the band gap, the C 2p states are introduced around the middle of the gap of C doped TiO2. The impurity states are occupied and maximum reduction in the band gap is found in Mo, C codoped TiO2. The addition of N in the Mo, C codoped TiO2 modified the band structure by creating isolated states in the band gap. The photo-response of Mo, C, N tri-doped TiO2 is prominent among the simulated models attributed to the step wise transition of electrons by the C 2p and N 2p states. The improved optical response allows more visible photons for absorptions but the isolated states may annihilate it. The Mo, C codoped system provided minimum structure changes with clear band structure and reasonable visible light absorption.