Complexation of iminocoumarin derivatives with BF3·OEt2 provides novel N^N boron(III) dyes exhibiting high absorption coefficients and quantum yields as great as 81%. The excellent chemical stability of these dyes enables the grafting of Boranil or Bodipy units to give derivatives in which the Borico subunit can act either as an energy acceptor or as an antenna for a red emitting fluorophore.