Treatment of RuHCl(CO)(PPh3)(3) with 1,3,5-triethynylbenzene produces the trimetallic complex 1,3,5-[Cl(CO)(PPh3)(2)RuCH=CH](3)C6H3, which reacts with PMe3 to give 1,3,5-[Cl(CO)(PMe3)(3)RuCH=CH](3)C6H3. 1,3,5-[Cl(CO)(PPh3)(2)RuCH=CH](3)C6H3 also reacts with pyridine (Py) and 4-phenylpyridine (PhPy) to give 1,3,5-[Cl(CO)(L)(PPh3)(2)RuCH=CH](3)C6H3 (L = Py, PhPy). Reactions of OsHCl(CO)(PPh3)(3) with ArCdropCH (Ar = Ph, p-tolyl) produce the six-coordinated insertion products OsCl(CH=CHAr)(CO)(PPh3)(3). Reaction of OsHCl(CO)(PPh3)(3) with 1,3,5-triethynylbenzene produces the bimetallic complex 1-HCdropC-3,5-[Cl(CO)(PPh3)(3)OsCH=CH](2)C6H3, which reacts with PMe3 to give 1-HCdropC-3,5-[OsCl(CO)(PPh3)(2)(PMe3)OsCH=CH](2)C6H3. The electrochemical and second-order NLO properties of some of the new complexes have been investigated.