The mononuclear amidinate complexes [(η 6 -cymene)-Ru-Cl(1a)] (2) and [(η 6 -C 6 H 6 )RuCl(1b)] (3), with the trimethylsilyl-ethinylamidinate ligands [Me 3 SiCϵCC(N-c-C 6 H 11 ) 2 ] -(1a -) and [Me 3 SiCϵCC(N-i-C 3 H 7 ) 2 ] -(1b -) were synthesized in high yields by salt metathesis. In addition, the related phosphane complexes [(η 5 -C 5 H 5 )Ru(PPh 3 )(1b)] (4a) [(η 5 -C 5