The reactions of the anion [X(CO) 2 Mo(μ-S 2 CPCy 3 )Mo(CO) 3 ] - (X=NO, η 3 -C 3 H 5 ) with Ph 2 PCl afforded the products [(ON)(CO) 2 Mo(μ-PPh 2 )(μ-S 2 CPCy 3 )Mo(CO) 3 ] (3) and [(η 3 -C 3 H 5 )(CO)Mo(μ-PPh 2 )(μ-S 2 CPCy 3 )Mo(CO) 3 ] (4), respectively. The chemical shifts of the resulting μ-PPh 2 ligands in the 3 1 P{ 1 H} NMR spectra indicate that the two molybdenum atoms are not bonded in 3, but are directly bonded in 4. The selenido-bridged binuclear complexes [X(CO) 2 Mo(μ-SePh)(μ-S 2 CPCy 3 )M(CO) 3 ] (X=NO, M=Mo, 5a; M=W, 5b; X=η 3 -C 3 H 5 , M=Mo, 6a; M=W, 6b) were synthesized by the reactions of the corresponding anions [X(CO) 2 Mo(μ-S 2 CPCy 3 )MCO) 3 ] - with PhSeI. The influence of the nitrosyl and allyl ligands on the formation of metal metal and metal carbon bonds in bimetallic complexes containing both S 2 CPCy 3 and PPh 2 bridges is discussed.