A new porous titanium(IV) squarate metal–organic framework (MOF), denoted as IEF‐11, having a never reported titanium secondary building unit, is successfully synthesized and fully characterized. IEF‐11 not only exhibits a permanent porosity but also an outstanding chemical stability. Further, as a consequence of combining the photoactive Ti(IV) and the electroactive squarate, IEF‐11 presents relevant optoelectronic properties, applied here to the photocatalytic overall water splitting reaction. Remarkably, IEF‐11 as a photocatalyst is able to produce record H2 amounts for MOF‐based materials under simulated sunlight (up to 672 µmol gcatalyst in 22 h) without any activity loss during at least 10 d.