A range of stable emulsions of spherical and rod-like conjugated polymer nanoparticles (CPN) can be synthesised via Suzuki-Miyaura cross-coupling reactions of 9,9-dioctylfluorene-2,7-diboronic acid bis(1,3-propanediol) ester with a number of different dibromoarene monomers in xylene, stabilised in water by the non-ionic surfactant, Triton X-102. High molar mass poly(9,9-dioctylfluorene) (PF8), poly(9,9-dioctylfluorene-alt-benzothiadiazole) (PF8BT), poly(9,9-dioctylfluorene-alt-4-sec-butylphenyldiphenylamine) (PF8TAA) and poly(9,9-dioctylfluorene-alt-bithiophene) (PF8T2) emulsions can be obtained, at high overall conjugated polymer concentrations (up to 11,000 ppm), in the presence of the palladium complex, (IPr*)PdCl2(TEA) and base, tetraethylammonium hydroxide, in nitrogen atmosphere at 30 oC after 24-48 hr. TEM analysis of the PF8 and PF8T2 emulsions revealed regular rod-like structures, up to 200 nm in length with aspect ratios of 4-5. This unprecedented self-assembly, which occurs during the polymerization reaction, provides high concentrations of anisotropic nanoparticles with useful photophysical and semiconducting properties. The optical properties of PF8 emulsions indicate high levels of ordered beta-phase configurations (9-10 %) in the rod-like nanoparticles which prove to be largely unaffected by changes in molar mass distribution of the polymer itself. PF8BT and PF8TAA form spherical particles with diameters of between 20-40 nm in TEM analysis. The concentrations of high molar mass conjugated polymers in the xylene present, in the resultant nanoparticles, are at levels up to 150 mg ml-1. It is perhaps best to consider the nanoparticles to be entities of the respective conjugated polymers in solid state. Conjugated polymer nanoparticles have many attractive features which are gaining interest in biomedical, photonic and electronic application areas. The processing of conjugated polymers for use in some of these applications is often complicated by solubility and viscosity issues, i.e. materials only soluble and processable in chlorinated solvents at higher temperatures. This CPN process offers the direct production of high concentrations of similar material, dispersed in an environmentally benign solvent (water) at room temperature at lower viscosities. The success of the process in emulsion conditions is aided by recently reported (N-heterocyclic carbene)-PdCl2(triethylamine) complexes which are moisture stable and can effectively catalyse the Suzuki-Miyaura reaction at room temperature.