The presented combination of chiral spectroscopic (electronic circular dichroism [ECD]) and chemical (phloroglucinolysis plus MS and chiral HPLC) analysis generated the necessary framework of chiral reference data that enables the determination of absolute configuration of catechol monomers in oligomeric PACs by 1D and 2D NMR. Access to the full 3D structure of PAC trimers, tetramers, and even higher oligomers in their native, underivatized form is critical to establish structure activity relationships from the subsequent biological evaluation, such as for the dentin biomodification potential of the compounds presented here, which were isolated from fractions with known bioactivity. The presented structural data expands both our prior reports as well as other PAC literature by providing accurately and precisely assigned C NMR resonances. This forms the knowledge base for making absolute stereochemical assignments of PAC monomers via inclusion of the -gauche effect observed in the C NMR resonances of PACs, as well as the determination of differential (s.c.s) C chemical shift values (C) relative to those in the terminal monomers and analogous dimers (here: 2 and 46).