Thiolene gold(I) and tin(IV) complexes such as [Au(ddtCO₂R)L] [L = PPh₃, PPh₂Me or AsPh₃; R = Et or Me; ddtCO₂R = 3-(alkoxycarbonylsulfanyl)-5,6-dihydro-1,4-dithiine-2-thiolate] and [Sn(ddtCO₂R)₂Me₂] have been obtained from solutions of TTBEO {2,5,7,9-tetrathiabicyclo[4.3.0]non-1(6)-en-8-one} with sodium ethoxide or methoxide and the corresponding halogeno-complexes [AuCl(L)] and SnMe₂Cl₂. Reaction of the same solutions with [N(PPh₃)₂]₂[ZnCl₄] and [ZnCl₂(N–N)] [N–N = 1,10=phenanthroline (phen) or 2,2′-bipyridine (bipy)] afforded the dithiolene complexes [N(PPh₃)₂]₂[Zn(dddt)₂], [Zn(dddt)(phen)] and [Zn(dddt)(bipy)] which are the transmetallating starting materials for the synthesis of dithiolene gold(I) and tin(IV) complexes [{Au₂(dddt)(AsPh₃)}_n], [Au₂(dddt)(PPh₃)₂], [Au₂(dddt)(PPh₂Me)₂] and [Sn(dddt)Me₂]. The results point to the existence of both thiolene ddtCO₂R^– and dithiolene dddt^2– species in TTBEO solutions with sodium alkoxide. The crystal structures of [Au(ddtCO₂Et)(PPh₃)] and [Sn(ddtCO₂Et)₂Me₂] confirm the presence of the ethoxycarbonylsulfanyl ligand.