Observations by Schweizer and Kopay (J. Org. Chem. 36 (1971) 1489) suggested the possibility of promoting ambident bonding behavior in transition metal complexes of phosphonium ylids of the type R 3 +P C R′C(O)R″ by a judicious choice of R groups. Accordingly, we have synthesized Pd II, Pt II, and Hg II chlorideylid complexes for ylids of the types R 3ZCR′R″ (Z = P, R = Ph, R′ = H, R″ = COPh, COCH 3, COOCH 2CH 3, COOCH 3, CN; R′ = CH 3, R″ = COPh, COOCH 2CH 3; R′ = COPh, R″ - COPh; R = n-C 4H 9, R′ = H, R″ = COPh; Z = As, R = Ph, R′ = H, R″ = COPh, COOCH 3), (CH 3) 2SCHCOPh, and C 5H 5NCHCOPh. The reactions of the ylids with PdCl 2 and PtCl 2 in refluxing CH 3CN yielded complexes having the general formula [M(ylid) 2Cl 2], whereas reaction with HgCl 2 in alcohol produced dinuclear complexes of the type [Hg 2(ylid) 2Cl 4], presumably involving bridging Cl − groups. Proton NMR data for the soluble complexes revealed a downfield shift of the methine proton resonances relative to those of the free ylids. The ν(CO) frequencies of the complexes exhibited blue shifts, relative to those of the free ylids, approaching those of the completely protonated ′ onium salts, which indicates coordination via the methine carbon atoms. Thiocyanate complexes of selected ylids exhibited N and S bonding modes, the former being favored by complexes of the least basic ylids.