Water solvated polymeric dyes and polymeric tandem dyes having a blue excitation spectrum are provided. The polymeric dyes are conjugated polymers that can include a thiophene-containing co-monomer. The polymeric tandem dyes further include a signaling chromophore covalently linked to the conjugated polymer in energy-receiving proximity therewith. Also provided are labelled specific binding members that include the subject polymeric dyes. Methods of evaluating a sample for the presence of a target analyte and methods of labelling a target molecule in which the subject polymeric dyes find use are also provided. Systems and kits for practicing the subject methods are also provided.