The cyclen-based ligand 1, possessing a [1,10]-phenanthroline moiety as a pendant arm, has been used as a ditopic ligand for the complexation of d- and near infrared (NIR) emitting (and) f-metal ions. This ligand forms kinetically stable complexes, 1 center dot Ln, with lanthanide ions such as Ln=ytterbium, neodymium, and lutetium (formed as a non-IR emitting reference compound), the synthesis and photophysical properties of which are described herein in detail. These 1 center dot Ln complexes were then used as building blocks for the formation of mixed d-f heteropolymetallic self-assemblies, where the phen moiety was used to complex a ruthenium (Ru(II)) ion, giving the d-f(3) complexes Ru center dot Ln(3) (Ln = Nd(III), Yb(III), Lu(III)). The formation of these supramolecular coordination conjugates was studied by using absorption and luminescence spectroscopy, while the solution structure of the Ru center dot Lu-3 was elucidated by H-1 NMR in D2O and H2O. Of these conjugates, both Ru center dot Nd-3 and Ru center dot Yb-3 displayed an intense NIR-emission in H2O at pH 7.4 (with Q(Yb)(L) = 0.073% and Q(Nd)(L) = 0.040%) and in D2O (with Q(Yb)(L) = 0.23% and Q(Nd)(L) = 0.10%). By comparison with their monometallic analogues Ln center dot 1 (Ln = Nd(III), Yb(III)), we demonstrate that our new design possesses an enhanced sensitization efficiency for lanthanide metal centered sensitization upon using the [Ru(phen)3] moiety (d -> f energy transfer) as a visibly exciting antenna, and we demonstrate that the intensity of the Ru(II)-based luminescence strictly correlates to the efficiency of the d -> f energy transfer processes.