Besides the exciting possibilities of using dye-sensitized solar cells (DSC) for solar energy application the fundamental science of the device is as thrilling.This talk summarizes our research and development in DSC and solar fuels. For example, in 2010, we initialized the breakthrough of using new electrolyte systems for DSC, which is now an exploding activity worldwide. We discovered that the so-called 35 dye, with bulky alkoxy donor groups to prevent recombination losses, gives high efficiencies (6.7%) with Co-complex based redox couples. This was at that time the world record for alternative redox systems. Recently Gratzel's group has taken the DSC world record of 12.3% using our Co-based electrolytes.