A review with 49 refs. The dye-sensitized nanocryst. injection solar cell employs transition metal complexes for spectral sensitization of mesoporous TiO2 films together with suitable redox electrolytes or amorphous org. hole conductors. Light harvesting occurs efficiently over the whole visible and near-IR range due to the very large internal surface area of the films. Judicious mol. engineering allows the photoinduced charge sepn. to occur quant. within a few femtoseconds. The certified overall power conversion efficiency of the new solar cell for AM 1.5 solar radiation stands presently at 10.4%.