Electrophoretic ink nanoparticles with high mobility are successfully fabricated by dispersion polymerization. The color of test cells can be changed by applying a bias voltage, as shown in the figure: the lower row shows the same cells as the upper row but with an applied voltage. These all-organic, encapsulated-dye, electrophoretic ink particles are expected to reduce the fabrication cost of e-ink in electrophoretic image display cells.