Electroactive polymers exhibit a change in properties, typically size or shape, in response to electrical stimuli. One class of electroactive polymer of particular interest are the conjugated polymers, whose conjugated backbone structure imparts electrical conductivity. However, this structure imposes processing limitations restricting their form to 2D structures. To overcome this, we develop specially formulated polyanilinebased blends via counter-ion induced thermal doping for the fabrication of 3D conductive structures via direct ink writing. This approach employs multi-material extrusion for the production of structures with passive and active features, rapid device fabrication, and improved design freedom. A model of the thermal doping and extrusion processes is proposed that enables designers to predict the extruded track width and tune process parameters as required. These processes have been applied to the fabrication of both standalone polyaniline-based 3D structures and embedded strain sensors capitalizing on the piezoresistive properties of polyaniline.