The formation of bio-derived materials is gaining momentum in academic and industrial research as a consequence of depleting petroleum resources, providing mid- and long-term alternative sustainable materials. In this context, we have prepared a series of terpolymers derived from the renewable terpene limonene producing polycarbonates with a controlled and variable ratio of incorporated nonfunctional cyclohexene oxide (CHO) and functional limonene oxide (LO) monomers. As catalyst, a simple binary combination of an Al(III) aminotriphenolate complex and PPNCl (PPN = bis(triphenyl)phosphine–ammonium) has been used to afford the targeted, partially bio-based polycarbonates with typically high carbonate content (>95%), good conversions, and a controllable amount of olefinic groups in the terpolymer backbone. Cross-linked polymers (CLP) have been easily obtained from these terpolymers through thiol–ene click reactions allowing for the preparation of interconnected networks with improved thermal properties with their Td in the range of 250–280 °C and with glass transitions (Tg) of up to 150 °C. A detailed analysis of the cross-linked polycarbonates demonstrates a clear relation between the percentage of potential cross-linking groups in the terpolymer precursors and the physicochemical properties including solubility, rigidity, and thermal stability.