Ethanol and rapeseed oil are mixed in presence of tributyl citrate, 2,5-dimethylfuran, 2-methylfuran, 2-methyl tetrahydrofuran, methyl tert butyl ether, ethyl tert butyl ether, FAME-rapeseed biodiesel, 1-heptanol and 2-ethylhexyl nitrate, at 25 °C (298.15 K). All these additives come, or can be obtained completely or partially from plants. The obtained ternary phase diagrams show a large domain of clear and homogeneous solutions and a liquid two-phase system due to the partial solubility of rapeseed oil and ethanol. All the tested additives have thus an evident co-solvent behavior for ethanol and rapeseed oil. In all the studied systems, the possible presence of nano-structures is checked with dynamic light scattering (DLS) and confirmed using static light scattering (SLS). In the system rapeseed oil/ethanol/1-heptanol, the presence of nano-structures is definitely established performing small-angle neutron scattering (SANS). The true geometry of these nano-structures could not be detected, but systematic conductivity measurements starting with the binary melt 1-heptanol/rapeseed oil in presence of LiClO4 adding ethanol show clearly a continuous transition from ethanol-in-rapeseed oil to rapeseed oil-in-ethanol mixtures passing through a bicontinuous medium.