The dithiolene ligand and tetrathiafulvalene precursor molecules 4,5-bis(bromomethyl)-1,3-dithiol-2-one and 4,5-bis[(dihydroxyphosphoryl)methyl]-1,3-dithiol-2-one

6,6-Dimethyl-2H,5H,6H,7H-1,3-dithiolo[4,5-f][1,5,3]dithia-silepin-2-one

In the structure of the title compound, C₇H₁₀OS₄Si, the carbonyl O atom lies in the plane of the five-membered dithiole ring with a deviation of only 0.022 (2) Å. The seven-membered ring adopts a chair conformation. The crystal packing is stabilized by S⋯O [3.096 (4) Å] and S⋯S [3.620 (4) Å] contacts, together with C—H⋯S inter­actions.