A fluorescent macromolecule comprising: a linear sequence-defined backbone; and a plurality of fluorophores attached to the backbone in a pre-determined order to form a fluorophore sequence, wherein the fluorophores in the fluorophore sequence are separated from one another by a distance permitting interaction between adjacent fluorophores such that the macromolecule emits fluorescence at a plurality of wavelengths when irradiated by light to form a fluorescence emission spectrum, and wherein the fluorescence emission spectrum has a profile that is determined by the fluorophore sequence.