This work describes the controlled organocatalytic ring-opening polymerisation (ROP) of cyclic carbonates with pendant groups for the preparation of functional aliphatic poly(carbonate)s and poly(estercarbonate) s. Their subsequent post-polymerisation functionalisations were studied yielding a range of functional aliphatic poly(carbonate)s. Chapter 1 reviews the preparation of cyclic carbonates with pendant functionalities, their ring-opening polymerisation and the postpolymerisation modifications of the resulting poly(carbonate)s. The properties and some applications of functional poly(carbonate)s are also discussed. Chapter 2, 3 and 4 describe the controlled ring-opening polymerisation of allyl- functional cyclic carbonate MAC (5-Methyl-5-allyloxycarbonyl-1,3- dioxan-2-one) and propargyl- functional cyclic carbonate MPC (5-Methyl-5- propargyloxycarbonyl-1,3-dioxan-2-one) using organic catalysts. Successful functionalisation of allyl-functional poly(carbonate)s was achieved via radical addition of thiol-containing molecules to the pendant allyl esters (Chapter 2), while functionalisation of propargyl-functional poly(carbonate)s was realised via the Huisgen 1,3-dipolar cycloaddition of azides to the pendant propargyl groups (Chapter 3). In addition, the copolymerisation of MAC and MPC and the subsequent orthogonal functionalisation of a copolymer was investigated (Chapter 4). Chapter 5 describes the copolymerisation of MAC (and MPC) with stereopure lactide, with resulting copolymers with opposite chiralities being succesfully applied in stereocomplexation. Chapters 6 summarises the results obtained in Chapters 2, 3, 4 and 5 whilst Chapter 7 provides the experimental methodologies.