Heterogeneous materials consist of multiple phases randomly distributed throughout the medium. Examples include voids and minerals in rocks, aggregates and cement paste in concrete, inclusions/fibres and polymer matrix in composites, and polycrystalline grain structures in alloys. The random morphology of these materials significantly influences their processing, structure, properties, and performance. For porous media, the distribution and connectivity of pore spaces critically affect flow transport within the material. In alloys, features such as grain size, orientation, and boundaries determine physical properties like strength and stiffness. This mini-symposium, without limiting itself to specific materials, focuses on the characterization, representation, simulation, and application of heterogeneous materials, respecting the heterogeneity of their microstructures. Topics include: • Characterization: Physical testing, microscopic imaging, and statistical analysis of various heterogeneous materials. • Representation: Digital reconstruction of microstructures or representative volume elements (RVEs) of heterogeneous materials. • Simulation: Multiscale modelling, multi-physics simulation, data-driven analysis and artificial intelligence of heterogeneous materials. • Applications: Microstructure design, process optimization, performance evaluation, and fabrication methods of heterogeneous materials. • Other related topics.