Thermal treatment of indenyl-functionalized imidazolium salts and N-heterocyclic carbenes with Ru3(CO)12gave different products. The normal mononuclear metal complexes (2a, 2b) were obtained viadirect reaction of indenyl-functionalized imidazolium salts (1a, 1b) with Ru3(CO)12. Unexpected intramolecular C–H activated products (3a, 3b, 4a, 4b) were obtained viathermal treatment of corresponding indenyl-functionalized N-heterocyclic carbenes. All complexes were determined by 1H NMR, 13C NMR, IR spectra and elemental analysis. The molecular structures of 2b, 3a, 3band 4bwere determined by X-ray diffraction. [ABSTRACT FROM AUTHOR]