Photochemical materials that act as bioreactors by exploiting the photosynthesis mechanism have been fabricated by entrapping whole plant cells within a porous silica matrix. The immobilisation step has been achieved via the in situ co-polymerisation of an aqueous silica precursor and a biocompatible trifunctional silane directly around cells. The cells remain undivided whilst the photochemical activity of the cells is well preserved over time. The design of a photochemical material that can act like a leaf, converting water into O and produce valuable organic compounds from CO under light irradiation is described. In particular, the increased excretion of polysaccharides by this photochemical material has been highlighted. The organic compounds formed have been extracted and analysed. The success of this work could open the door to new exciting photochemical materials with long-term photosynthetic activity and stability and to new green chemical processes for the conversion of solar energy into chemical energy with a concomitant reduction in CO. © 2010 The Royal Society of Chemistry.