A polymer composition that has an in-plane thermal conductivity of about 2.0 W/m-K or more is provided. The composition comprises 100 parts by weight of at least one aromatic polymer; from about 10 to about 50 parts by weight of an inorganic material having a hardness value of about 2.5 or more based on the Mohs hardness scale; and from about 20 to about 80 parts by weight of a thermally conductive particulate material having an average size of from about 1 to about 100 micrometers.