[Au(NTf2)(NHC)] is known to provide the respective digold-acetylide complex with a -and a -bound NHC-gold complex (Widenhoefer dimer). The analogous reaction is reported here using the green and red fluorescent gold complexes 13 and 14 to provide the dinuclear complex 16 (scheme 4). A solution of the red gold complex 14 in 1,2-dichloroethane was added to a solution of the green gold complex 13 in the same solvent in a fluorescence cuvette at t= 7 min. The reaction mixture was irradiated with 505 nm light and the fluorescence in the red channel (648 nm) and in the green channel (535 nm) observed (fig. ). The reaction ensues after mixing both reactants and the formation of the dimeric gold complex is evidenced by a pronounced decrease in the green 535 nm emission and a corresponding increase in the red 648 nm emission due to FRET (fig. ). The green emission decreases to 14% of the initial value. In contrast to dyad 12 the resonance energy transfer is not quantitative, which is hardly surprising, because the distance between the green and the red fluorophore is much larger. Considering the flexibility of the red and green subunits of the molecules it is likely, that the FRET is isotropic and orientation factors need not be considered. Because of this flexibility it is also difficult to obtain precise information on the average distance between the green and the red fluorophore. Based on the observed FRET the distance between the red and the green Bodipy in 16