In photosynthetic organisms, the light driven energy supply has been superimposed on a pre-existing set of primary metabolic reactions based on energy generation from oxidation of chemical compounds present in the environment (i.e. chemoautotrophs) and formation and turn-over of carbohydrates as a mean to channel energy flux and carbon into specific biosynthetic pathways. Inherent limitations in the ability of photosynthesizing organisms to channel the use of light-generated reducing equivalents directly into synthesis of specific compounds may reflect this evolutionary history. Photosynthetic organisms, such as cyanobacteria, algae and plants, are thus amenable to the use of synthetic biology approaches aimed at tapping directly into, and prioritizing the energy output from, photosynthesis towards the efficient production of desired products. Strategies to reach this goal based on the optimized expression of desired biosynthetic enzymes or entire pathways in the chloroplast stroma or thylakoid membranes will be discussed with focus on the development of a model system synthesizing the cyanogenic glucoside dhurrin and subsequent systems producing high value structurally complex diterpenoids for medical uses.