Organic photovoltaic (OPV) has been exciting tremendous interest over the last decade. Nowadays, power conversion efficiencies (PCE) over 9 % with small molecule-based organic solar cells (OSCs) are achieved [1, 2]. However, high efficiency solar cells go in hands with highly complex molecular structure of organic semi-conductors. To be economically viable, industrial application of small-sized molecular donors requires the rapid development of cost-effective and green synthetic methodologies that allow producing large-scale batches of high-purity materials [3]. Nature uses conventional nucleophilic reactions to produce π-conjugated molecules from simple natural precursors. Based on this observation, we synthesized a family of organic semiconductor inspired by curcumin, a natural dye from the rhizome of turmeric (Curcuma Longa L.). The metal-free synthesis was performed in one pot and leads to yields above 70 %. We specifically designed these curcuminoid derivatives with donor-acceptor-donor structure for OSCs. In combination with [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM), they act as efficient donor materials in solution-processed bulk-heterojunction (BHJ) OSCs. For some molecules, promising PCE above 4 % have been achieved. Best OSCs exhibit particularly high open circuit voltage (VOC) over 1.0 V. Results show the high potential of these structures as molecular scaffolds on which to base the design of optimized donor materials for BHJ OSCs.