Linking molecular fragments through chemical bonds to generate more complex species defines synthetic chemistry. Isolation of newly generated molecules allows their identification using established physical techniques, like NMR spectroscopy. In a non-covalent setting the species generated are characterized by significant dynamics and the rapid interconversion of numerous species may preclude the isolation of a single reaction product whose formation is governed by numerous equilibria involving the individual building blocks. In such cases it may be difficult to establish connectivities between the different molecular fragments. FRET is a potential tool to study molecular interactions and dynamic changes. Primarily in biochemistry, biology and medicine the use of fluorescent dyes utilizing FRET (fluorescence or Förster resonance energy transfer) is ubiquitous and known to provide information about conformational changes involving proteins and DNA or intracellular dynamics, but also in polymer chemistry and supramolecular chemistry. FRET is a non-radiative process in which an excited donor dye transfers energy to an acceptor dye in the ground state through long-range dipole/dipole interactions. This approach relies crucially on suitable fluorescent dyes (FRET pairs) developed in the last couple of decades, and which are characterized by proper functional groups to enable bioconjugation and compatibility with typical biochemical environments and aqueous solutions. Organometallic chemistry mostly takes place in a non-aqueous environment, rendering fluorophores used in biochemistry less suitable. Lewis basic heteroatoms are undesirable in organometallic chemistry, since they potentially coordinate the metal centers. Bodipy based dyes are proving to be very useful in organometallic chemistry. Numerous applications of this dye for mechanistic studies of chemical reactions involving single molecules or single particles utilizing fluorescence microscopy have been reported -with major contributions by the Blum group. However, only a few FRET pairs based on Bodipy dyes have been reported in the literature. Diederich et al. reported on a FRET pair composed of a green and a red Bodipy FRET pair, which were attached to a resorcin [4]arene cavitand. A Förster radius of approx. 3.7 nm was determined, which is huge compared to the size of typical organometallic complexes. Conceptual work from Lim and Blum reports on a palladium complex incorporating an allylic ligand tagged with a green fluorophore and a phosphine ligand tagged with an orange fluorescent dye in the coordination sphere. Upon green excitation the close vicinity of the two dyes leads to efficient resonance energy transfer evidenced by an orange fluorescence upon excitation of the green Bodipy. Plenio et al. utilized the Diederich FRET pair in NHC-metal complexes to achieve large virtual Stokes shifts for CO detection. The same group showed for closely related fluorophores, that FRET is also observed upon dimerization of NHC-gold complexes. However, significant problems for practical applications remain. The synthesis of the previously used red Bodipy is cumbersome and furthermore the chemical stability of the Diederich red Bodipy in an organometallic environment is rather limited and significantly improved red fluorophores are clearly needed.