We report a new family of titanium–organic frameworks that enlarges the limited number of crystalline, porous materials available for this metal. They are chemically robust and can be prepared as single crystals at multi‐gram scale from multiple precursors. Their heterometallic structure enables engineering of their photoactivity by metal doping rather than by linker functionalization. Compared to other methodologies based on the post‐synthetic metallation of MOFs, our approach is well‐fitted for controlling the positioning of dopants at an atomic level to gain more precise control over the band‐gap and electronic properties of the porous solid. Changes in the band‐gap are also rationalized with computational modelling and experimentally confirmed by photocatalytic H2 production. Metal doping in titanium MOFs: MUV‐10 are crystalline, porous titanium frameworks with excellent chemical stability in water. The presence of heterometallic clusters in the structure of the frameworks enables chemical engineering of the band‐gap by suitable doping with open shell metals rather than by linker functionalization. This observation is confirmed by computational modelling of the electronic structure of this family of solids.