In comparison with metals and polymers, ceramics and/or carbon are more difficult to process into well-defined cellular architectures (e.g., cubic, tetrakaidecadehron, etc.) using Additive Manufacturing techniques. The present work reports a simple method for generating complex and precise SiCN ceramic lattices using a preceramic polymer and applying the replica approach to structures fabricated using stereolithography of plastic materials, with the associated ease of fabrication. Three-dimensional printed plastic lattices impregnated with a polysilazane were converted to SiCN by pyrolysis at 1000 degrees C in inert atmosphere. In spite of the high amount of mass loss (similar to 58%) and volume shrinkage (similar to 65%), the impregnated structures did not collapse during pyrolysis, leading to highly porous (total porosity similar to 93 vol%) components possessing suitable strength for handling and potential use as lightweight components.