Polymers with "hairy-rod" architecture having oligo/polythiophene (PTh) as main chain and poly (ethylene glycol) (PEG) (M-n = 2000) as flexible side chains were obtained by combining the "macromonomer technique" with specific methods for the synthesis of conjugated polymers. Fluorescent nanoparticles of core-shell type with high colloidal stability were obtained from these water self-dispersible materials by a direct dissolution method in aqueous media. It has been shown that the size and photophysical properties of the micellar nanoparticles in aqueous dispersions as well as the bulk properties of the investigated materials can be tuned by varying the PEG side chain density and by the modality of PEG connection to the PTh main chains. The presence of the PEG shells in the structure of these fluorescent nanoparticles cans suppress the non-specific interactions with biomolecules on the one side and on the other side they work as a biomimetic interface that could facilitate their potential use as cell-imaging agents. The present attempt offers an ease of access alternative to conducting polymer nanoparticle encapsulation in a biocompatible matrix by nanoprecipitation.