Straightforward manufacturing pathways toward large-scale, uniformly layered composites may enable the next generation of materials with advanced optical, thermal, and mechanical properties. Reaction–diffusion systems are attractive candidates to this aim, but while layered composites theoretically could spontaneously arise from reaction–diffusion, in practice randomly oriented patches separated by defects form, yielding nonuniformly patterned materials. A propagating reaction front can prevent such nonuniform patterning, as is the case for Liesegang processes, in which diffusion drives a reaction front to produce layered precipitation patterns. However, while diffusion is crucial to control patterning, it slows down transport of reactants to the front and results in a steady increase of the band spacing as the front advances. Here, we circumvent these diffusive limitations by embedding the Liesegang process in mechanically responsive hydrogels. The coupling between a moving reaction front and hydrogel contraction induces the formation of a self-regulated transport channel that ballistically carries reactants toward the area where patterning occurs. This ensures rapid and uniform patterning. Specifically, large-scale ( > 5-cm) uniform banding patterns are produced with tunable band distance ( d = 60 to 160 µm) of silver dichromate crystals inside responsive gelatin–alginate hydrogels. The generality and applicability of our mechanoreaction–diffusion strategy are demonstrated by forming patterns of precipitates in significantly smaller microscopic banding patterns ( d = 10 to 30 µm) that act as self-organized diffraction gratings. By circumventing the inherent limitations of diffusion, our strategy unlocks the potential of reaction–diffusion processes for the manufacturing of uniformly layered materials.

The discovery of self‐organization principles that enable scalable routes toward complex functional materials has proven to be a persistent challenge. Here, reaction‐diffusion driven, immersion‐controlled patterning (R‐DIP) is introduced, a self‐organization strategy using immersion‐controlled reaction‐diffusion for targeted line patterning in thin films. By modulating immersion speeds, the movement of a reaction‐diffusion front over gel films is controlled, which induces precipitation of highly uniform lines at the reaction front. A balance between the immersion speed and diffusion provides both hands‐on tunability of the line spacing () as well as error‐correction against defects. This immersion‐driven patterning strategy is widely applicable, which is demonstrated by producing line patterns of silver/silver oxide nanoparticles, silver chromate, silver dichromate, and lead carbonate. Through combinatorial stacking of different line patterns, hybrid materials with multi‐dimensional patterns such as square‐, diamond‐, rectangle‐, and triangle‐shaped motifs are fabricated. The functionality potential and scalability is demonstrated by producing both wafer‐scale diffraction gratings with user‐defined features as well as an opto‐mechanical sensor based on Moiré patterning.