Biomass, a byproduct of natural photosynthesis, has been explored for its potential conversion into energy carriers, particularly biofuels. However, acknowledging the long-term limitations in biomass supply, as highlighted by the European Commission in the EU Bioeconomy Strategy Progress Report (2022), there is an urgent need for the development of advanced bioinspired technologies that mimic nature but exhibit higher efficiency. The S2B project aims to unlock the potential of photosynthetic microbes for the direct conversion of solar energy and CO2 into butanol by employing innovative concepts and approaches. Specifically, S2B will transfer the microbial production of butanol from conventional suspension cultivation to a tailored solid-state biocatalytic platform. In this platform, engineered thin-layer assemblies of cyanobacteria and bio-based matrix materials will synergistically enable the redistribution of cell resources, such as energy and carbon flows, towards butanol formation. Simultaneously, S2B will improve light management, enhance CO2 capture efficiency, and facilitate downstream processes by separating butanol from the production medium. Consequently, the primary technological innovation of S2B will be the continuous, long-term direct solar butanol production by photosynthetic cell factories acting as biocatalysts. The process will be integrated with waste effluent and direct air capture, covering the entire value chain from light harvesting and CO2 capture to product separation through the circular economy concept. Acting as a multidisciplinary consortium, S2B will construct a TRL4-level prototype, paving the way for a smooth upscaling process.