For these reasons, a wide range of materials are being 3D printed to advance fields ranging from tissue engineering to architecture. Additionally, unlike traditional electronics, extrusion printing is well suited for soft materials, like hydrogels, commonly used in iontronics. While iontronic materials have been 3D printed, these prints usually consist of a single, uniform material that can act as an electrode or strain/pressure sensor, but otherwise has no further computational capabilities. In contrast, with multi-material 3D printing, we can rapidly fabricate entire circuits where the interaction between different materials provide functionality, like ionic diodes. In this work, we highlight the adaptability of multi-material 3D printing by iterating the ionic diode design by only changing the 3D model (Figure ). While ionic diodes are traditionally sensitive to strain, we use the rapid iteration process afforded by 3D printing to fabricate and test a brand new geometry that is insensitive to strain. Again changing just the 3D model, we then integrate extrusion printed ionic diodes into more complex architectures. While soft electronics often focus only on the bulk properties of their materials, we use 3D printing to fabricate a structure designed for complex mechanical behavior, specifically strain stiffening behavior, which can be adjusted by changing specific parameters. Using the previously established methods, this iteration and integration of different components would be quite tedious, labor intensive, and challenging to achieve, whereas we implemented these changes immediately by updating the printing file, reducing the amount of cost, material waste, and time required. Multi-material printing makes rapid prototyping, personalized devices, complex iontronic circuits, and integrated soft electronics and mechanics more accessible in a highly reproducible manner, lowering the barrier to the next generation of soft iontronics. By combining multi-material 3D printing with iontronics, we provide a foundation for the rapid development and real-world application of increasingly complex soft iontronic devices. produce a range of soft electronic devices (v-vii) with different behavior and complexity. An ionic diode that is sensitive to strain (v) or insensitive to strain (vi) are printed using the same process. Ionic diodes can easily be incorporated into more complex designs with advanced mechanical properties, strain-stiffening behavior in this example (vii). All scale bars (white) represent 5 mm. 3D printing not only enables the structure to be easily adapted, but the inks can also be optimized according to their purpose and application. In order to highlight the adaptability of soft materials, we thoroughly characterize the photopolymerizable ink and the resulting conductive hydrogel we developed for extrusion printing ionic diodes. Previously, power sources were connected to ionic diodes via traditional metal electrodes, liquid metal, or aqueous salt reservoirs. Traditional metals and liquid metals are not well suited for extrusion printing, and do not align with the goals of viscoelastic iontronics. Atomic salts in a hydrogel reservoir may also diffuse out when wet if the gel is not completely enclosed. Alternatively, carbon nanotubes offer a popular conductive additive for soft materials, however they do not contribute to the elastic nature of the material nor to the ionic conductivity. Instead, mixed ionic-electronic polymer blends, like poly (3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS), interface well with both ionic systems and electronic systems and can directly provide viscoelastic characteristics desired in 3D printed materials and soft materials. By integrating this polymer mix within an acrylamide (AM) hydrogel, we establish a double network material that remains stable in aqueous environments. We prove that this material is a suitable upgrade to ionic diodes, allowing them to maintain functionality even when submerged in distilled water for prolonged periods of time.