In this review, we report and discuss the specific linear and nonlinear optical properties (two-photon absorption) of original 5-substituted-1,10-phenanthroline-based Ru(II) complexes. The perspective of applications in optical power limiting (OPL) and (two-photon excited) photodynamic therapy (2PE-)-PDT, are presented together with our strategy developed in collaboration, towards the elaboration and the use of the related functionalized nano-edifices obtained by encapsulation or covalent grafting. Multifunctional nano-platforms (NPs) with potential new properties or applications are described and particularly explained by the confinement of the molecular complexes within (or at the surface of) these NPs. The stability, inertness and versatility of the involved Ru(II) complexes are more particularly highlighted in order to fit the requirements.