Electronic structures of rutile and anatase polymorph of TiO 2 were determined by resonant inelastic X-ray scattering measurements and FEFF9.0 calculations. Difference between crystalline structures led to shifts in the rutile Ti d -band to lower energy with respect to anatase, i.e., decrease in band gap. Anatase possesses localized states located in the band gap where electrons can be trapped, which are almost absent in the rutile structure. This could well explain the reported longer lifetimes in anatase. It was revealed that HR-XAS is insufficient to study in-depth unoccupied states of investigated materials because it overlooks the shallow traps. Graphical Abstract The resonant X-ray emission spectroscopy around Ti k-edge was applied to probe local electronic structure of TiO 2 rutile and anatase. By measuring 1s→3d excitation and 3p→1s decay channel, differences between localized and delocalized orbitals were determined. The 3d pre-edge structures were compared with ab initio multiple scattering simulations.