These findings highlight that Ru(II) dyads derived from α-oligothiophenes directly appended to 1,10-phenanthroline-namely 2 and 3-possess low-lying <sup>3</sup> IL states that are highly photosensitizing, and they may therefore be of interest for photobiological applications such as photodynamic therapy (PDT).
The photosensitizing efficiencies of these Ru(II)-photosensitizer-immobilized nanoparticles for the O<sub>2</sub> evolution reaction catalyzed by the Co(II)-containing Prussian blue analogue [Co<sup>II</sup>(H<sub>2</sub>O)<sub>2</sub>]<sub>1.31</sub>[{Co<sup>III</sup>(CN)<sub>6</sub>}<sub>0.63</sub>{Pt<sup>II</sup>(CN)<sub>4</sub>}<sub>0.37</sub>] decreased as the number of Ru(II)-photosensitizing layers increased.