Easy access to strongly fluorescent higher homologues of BODIPY.

We present the easy and high yield synthesis of several group 13 Mes DPM compounds (Al-In) with alkyl substituents at the metal atom. All these compounds were fully characterized using techniques including X-ray diffraction analysis and photoluminescence measurements. It shows that for aluminium and gallium pronounced green fluorescence is observed, which is absent for indium. DFT calculations confirm that the first electronic transition corresponds to a ligand-based π-π* transition.