Topology optimization algorithms allow the design of optimized structures under prescribed constraints, loads, and boundary conditions. With such classical approaches the topology undergoes continuous changes during optimization iterations [1]. In this contribution, in order to deal with the challenges posed by large-scale topology optimization, we propose a novel structural optimization framework in which the structural topology is optimized by means of a multi-material approach [2] while at the macroscale the geometry of the domain is kept fixed. The formulation leverages on the selection of suitable non-periodic architectures at the microscale, such as spinodal configurations [3], which allow to explore a wide class of topologies. In order to illustrate the key features of the proposed approach as well as its applications to additive manufacturing, numerical examples are presented and several benchmark optimized structures are manufactured by means of an innovative powder-bed large-scale 3D printing technique. REFERENCES [1] Senhora, F. V., Sanders, E. D., and Paulino, G. H. (2022). Optimally-Tailored Spinodal Architected Materials for Multiscale Design and Manufacturing. Advanced Materials, 34(26), 2109304. [2] Sanders, E. D., Aguil´o, M. A., and Paulino, G. H. (2018). Multi-material continuum topology optimization with arbitrary volume and mass constraints. Computer Methods in Applied Mechanics and Engineering, 340, 798-823. [3] Vidyasagar, A., Kr¨odel, S., and Kochmann, D. M. (2018). Microstructural patterns with tunable mechanical anisotropy obtained by simulating anisotropic spinodal decomposition. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 474(2218), 20180535.