Abstract We introduce Lumina-DiMOO, an open-source foundational model for seamless multimodal generation and understanding. Lumina-DiMOO sets itself apart from prior unified models by utilizing a fully discrete diffusion modeling to handle inputs and outputs across various modalities. This innovative approach allows Lumina-DiMOO to achieve higher sampling efficiency compared to previous autoregressive (AR) or hybrid AR-diffusion paradigms and adeptly support a broad spectrum of multimodal tasks,...