Persulfides are receiving increased attention due to their links to hydrogen sulfide (H 2 S) and hydrogen polysulfide (H 2 S n ). Their close analogues selenyl sulfides (RSeSHs), however, have limited literature precedent, and their reactivity and possible role in biology are largely unknown. Here, we devised an acyl selenyl sulfide template to study RSeSH chemistry. Their stability and reactivity toward amines/thiols were studied. These compounds can produce H 2 S or H 2 S 2 under different conditions, suggesting that RSeSHs are possible intermediates.