The process is operationally simple and does not require an inert atmosphere, which is more robust than related anionic ring-opening polymerizations. Running at ambient temperature, the formation of hazardous byproducts such as hydrogen sulfide is completely avoided. The polymerization was also investigated computationally, revealing an intriguing self-correcting mechanism that ensures selective formation of trisulfide links in the repeating unit, rather than disulfide or tetrasulfide links that could conceivably form through alternative, but kinetically unfavored, pathways. With reliable access to poly(trisulfide) materials, several applications were explored including high-yielding depolymerization for monomer recycling, gold and copper sorption and recovery, and covalent modification post-polymerization.