Synthesis of red and green NHC-metal complexes. Red Bodipy-substituted azolium salts were synthesized as outlined in scheme 1. The literature procedure for the cyclization of the tosylated pyrrole 1 to the spiro-Bodipy was modified. In our hands the original procedure for the Pd/phosphine catalyzed ring-closing reaction generates significant amounts of the undesired -isomer instead of the desired -isomer (scheme 1), whose separation is difficult. Since it is known, that direct arylation reactions do not necessarily require additional phosphine ligands, ligand-free approaches for the cyclization were tested and optimized. Using Pd(OAc)2 in DMF in the absence of phosphine provides the -isomer as the predominant cyclization product in 70% yield (-isomer <1%). The detosylation of spiro-pyrrole was done by simply stirring the protected pyrrole with Cs2CO3 base in THF/MeOH and gave spiro-pyrrole 3 in 85% yield. The reaction of spiropyrrole 3 with benzaldehydes provides the respective Bodipy derivatives 4 and 8•HBr following established procedures for related compounds. The alkylation of the phenolic hydroxy-imidazolium salt with 4 provides azolium salt 5•HBr tagged with a red spiro-Bodipy. This ether forming reaction requires very long alkyl chains (here -(CH2)10Br), since for shorter linkers, like (-(CH2)6Br) significant product formation was not observed. Comparable observations were made before and the lack of reactivity for the shorter linkers is attributed to the steric bulk of the two building blocks (spiro-Bodipy and imidazolium salt). It is possible to establish Bodipy-tagged imidazolium salts with shorter linkers using a different order of the synthetic steps (scheme 1). A -C6H4(CHO) terminated azolium salt 7•HBr was synthesized and this aldehyde condensed with spiro-pyrrole 3 to the respective Bodipy-tagged azolium salt.