Electrophoretic mobilities of copper phthalocyanine (CuPc) pigment particles dispersed in Isopar G™ are reported. The mobilities were measured as a function of particle charging agent (PCA) concentration using phase analysis light scattering (PALS). The role of particle stabilizing agents (PSAs) at the particle surface was also investigated. An equilibrium site binding model can describe the experimental data adequately. Conductivity measurements and adsorption isotherms facilitate an overall description of particle charging in these systems. The electric field dependence of the electrophoretic mobility of the pigment particles was also investigated up to field strengths of 10⁴ V cm⁻¹ and showed a marked dependence on the strength of the applied field. A modified version of the model proposed by Jin and co-workers in Ref. 18. is used to model the field dependence.