In conclusion we have presented a comprehensive study on CO2/CHO and CS2/CHO ROCOP employing a series of new heterobimetallic catalysts which eventually allowed to combine both processes in CO2/CS2/CHO ROTERP. We found that heterobimetallic cooperativity in terms of rate and selectivity is maintained when moving from CO2 to CS2 which is due to structurally analogous ratedetermining steps that are more easily overcome with less Lewis acidic alkali metals. Furthermore, while the well-established catalytic system employing two components performs well in CO2/CHO ROCOP, CS2/CHO ROCOP clearly benefits from the state-ofthe-art strategy. We found the mechanistic origin behind O/S scrambling to be backbiting reactions in which metal alkoxide chain-ends attack heterocarbonate links. Hereby those transform into metal thiolate chain-ends under oxygen enrichment of the adjacent (hetero)carbonate link which then themselves either eliminate thiiranes to form metal(hetero)carbonate chain-ends or propagate. The fact that CS2/CHO ROCOP can be understood as a series of interconnected ROCOP cycles 3.5 6.0 eventually allowed for CO2/CS2/CHO ROTERP generating polycarbonates with some interspersed sulfur containing linkages. Sulfuration as little as one out of twenty heterocarbonate links was found to impart chemical and photodegradability onto the parent CO2 copolymers which is attractive given that oxidation and photolysis represent the initial breakdown pathways of polymer waste in nature. Our study demonstrates how mechanistic understanding can allow the control of complex catalytic systems for the valorisation of CO2 into new degradable materials which could be transferable to many other ringopening polymerisations.