Trithiapentalene is an organic bicyclic molecule containing two sulfur heterocycles.

Its 10-π aromatic structure is similar to naphthalene.

There has been a literature dispute about whether the connectivity among the three sulfur atoms is a case of rapid tautomerization between two valence tautomers or a 3-center 4-electron bond.

[2] The reactions have been little studied.

It forms a dinickel complex upon reaction with bis(allyl)nickel.