Hollow octahedrons of polyaniline (PANI) were prepared using Cu2O as a template in the presence of H3PO4 and (NH4)(2)S2O8 as a dopantand an oxidant, respectivcely (see figure). The Cu2O template can be used to prepare different morphologies of PANI (e.g., hollow octahedrons and psheres). Compared with other conventional templates, the Cu2O template is unique (in terms of both body shape and quality) and omits the need for template-removal treatment.