The specification describes various polymers having monomer of formula (I): In formula (I), R1 and R2 are, independently, hydrogen, a C1-C24 alkyl group, an aromatic or heteroaromatic group, a C3-C8 cycloalkyl or C2-C7 heterocycloalkyl group, or a —C(O)R3 group in which R3 is a C1-C24 alkyl group, an aromatic or heteroaromatic group, a C3-C8 cycloalkyl or C2-C7 heterocyclic group; or a —CH2—C(O)—R4 group in which R4 is a C1-C6 alkyl group. At least one of R1 and R2 is a —C(O)R3 group. The polymer may be a homopolymer or a copolymer containing other ethylenically unsaturated monomers. The polymer may be used in a variety of coating compositions such as inks, adhesives, paints and films. Unique monomers where both R1 and R2 are acetoacetyl groups and novel monomers where R2 is an acetoacetyl group are also described.