The rising levels of electronic waste, projected to surpass 82 million metric tons annually by 2030, highlight the need for sustainable materials in electronics. Continued reliance on non-decomposable substrates (glass, FR4-epoxy laminates, plastic foils, etc.) and scarce transparent conductors as electrodes will only intensify pollution and high-emission manufacturing. A decomposable platform compatible with reflow soldering and thin-film device fabrication could address these gaps. Here, the emerging field of “Leaftronics” offers a solution by extracting quasi-fractal lignocellulosic venation from leaves to form robust scaffolds that integrate solution-processed biopolymers into high-performance substrates or, when metallized, transparent electrodes for optoelectronics. We discuss how leaf-derived structures help to fabricate flexible, transparent substrates with <1 nm surface roughness, support reflow-soldered circuits, vapor-deposited devices, printed transistors, and batteries. The approach demonstrates full decomposability, component recovery, and >90% reduced carbon footprint (cradle-to-gate) versus conventional approaches. Recent advances in fractal metallization for superior transparent electrodes are reviewed, suggesting leaf venation as a model for enhancing bio-composites using natural hierarchies. Pathways to translation and future research horizons are outlined. By merging evolutionary designs with biopolymers, “Leaftronics” paves a scalable path to low-waste electronics, inspiring interdisciplinary investigations in biomimetic materials and sustainable device architectures.