Plant Polyphenols LLC is focused to exploiting agricultural and forest industry processing residues as a source of flavanoids of defined absolute stereochemistry for semi-synthesis of a variety of polyflavanoid derivatives. These compounds are well known for their potent anti-oxidant, anti-cancer, and anti-microbial properties. Highlights selected from past research on these compounds (also known as proanthocyandins or condensed tannins) are presented to demonstrate their structural diversity, conformational properties, and interactions with peptides or proteins. Examples of current semi-synthesis efforts to provide pure compounds up to gram quantities are reviewed. By providing pure compounds, with assurance of being able to scale up to large quantities, we hope to help biologists to define the potential of these compounds to improve human health.