The grand challenge of closing the carbon cycle for large-­‐scale produced plastics such as polyolefins is addressed. Rather than being considered waste, these will serve as raw materials to produce novel polymers with superior physical properties and recyclability, and to produce value-­‐added, well-­‐defined low molecular building blocks. Homogeneous and heterogeneous catalysts will be deployed in a concerted fashion to design energy efficient and selective processes. Unsaturation, created in the polymer chains, serves as a handle to cut-­‐and-­‐paste the chains into new polymers via homogeneously catalyzed reactions. Preliminary key proof-­‐of-­‐concept experiments highlight the feasibility of the proposed work. The consortium is comprised of seasoned and junior catalysis and polymer scientists, with strong experience in substrate conversion into value-­‐added compounds and materials.