The ruthenium(II) complexes [Ru(CHCHR){κ2-S2P(OEt)2}(CO)(PPh3)2] (R = But, C6H4Me-4) are formed on reaction of (NH4)[S2P(OEt)2] with [Ru(CHCHR)Cl(CO)(BTD)(PPh3)2] (BTD = 2,1,3-benzothiadiazole), while the enynyl complex [Ru(C(CCPh)CHPh)Cl(CO)(PPh3)2] loses a phosphine on treatment with the same ligand to yield [Ru(η3-PhCC–CCHPh){κ2-S2P(OEt)2}(CO)(PPh3)]. The stilbenyl complexes [Ru(CPhCHPh)Cl(CA)(PPh3)2] (A = O, S) react with (NH4)[S2P(OEt)2] to provide the dimers [Ru(CPhCHPh){μ–κ1–κ2–S2P(OEt)2}(CA)(PPh3)]2. Treatment of the thiocarbonyl complex with carbon monoxide results in migratory insertion of the vinyl and CS ligands to provide [Ru(η2-SCCPhCHPh){κ2-S2P(OEt)2}(CO)(PPh3)]. On treatment with excess 4-ethynyltoluene, the known compound [RuH{κ2-S2P(OEt)2}(CO)(PPh3)2] undergoes insertion of the alkyne to provide an alternative route to [Ru(CHCHC6H4Me-4){κ2-S2P(OEt)2}(CO)(PPh3)2]. The compounds [Ru(CHCHR){κ2-S2P(OEt)2}(CO)(PPh3)2] (R = n-C4H9, CH2OSi(But)Me2, CO2Me, Fc, CPh2OH, (HO)C6H10) were prepared cleanly by this route using HCCR. On stirring [RuH{κ2-S2P(OEt)2}(CO)(PPh3)2] over a longer period of time with excess 4-ethynyltoluene, the acetylide [Ru(CCC6H4Me–4){κ2-S2P(OEt)2}(CO)(PPh3)2] is generated. Heating [Ru(CHCHC6H4Me-4){κ2-S2P(OEt)2}(CO)(PPh3)2] with excess 3,3-dimethylbut-1-yne in 1,2-dichloroethane led to elimination of the vinyl ligand and formation of the acetylide compound [Ru(CCBut){κ2-S2P(OEt)2}(CO)(PPh3)2]. A small amount of the side product, [RuCl{κ2-S2P(OEt)2}(CO)(PPh3)2], was also formed. This could be obtained directly from the reaction of [RuH{κ2-S2P(OEt)2}(CO)(PPh3)2] with N-chlorosuccinimide. The related mixed-donor ligand, K[OP(S)(OEt)2], reacts with [Ru(CHCHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] to yield [Ru(CHCHC6H4Me-4){κ2-OP(S)(OEt)2}(CO)(PPh3)2]. The molecular structure of [Ru(CHCHCPh2OH){κ2-S2P(OEt)2}(CO)(PPh3)2] was determined crystallographically.