The discovery and synthesis of thiolato bridged dinuclear arene ruthenium complexes are described and discussed.

The complexes can be obtained as mono-, di-, or trithiolato complexes.

Trithiolato complexes are among the most cytotoxic ruthenium ever reported.

One trithiolato complex, diruthenium-1, significantly prolongs the survival of tumor-bearing mice.

Trithiolato complexes do not hydrolyze and remain inert toward amino acids, proteins, and nucleotides.

Conjugation to various biological active moieties is expected to increase their and cellular uptake and selectivity.