Recent developments in NMR hardware have extended the reach of natural products chemists to structure elucidation of compounds isolated on a nanomolar scale. In parallel with advances in hardware new NMR techniques for structure elucidation have evolved, e.g. quantitative NOEs, residual dipolar couplings (RDCs)and diffusion-ordered spectroscopy (DOSY). The application of recent NMR techniques was utilized in the screening and structural assignment of natural products isolated from a 2004 collection of South African tunicates. Assignment of the planar structures of mandelalides A-D from a new Lissoclinum sp. was feasible only after data acquisition on a 700 MHz magnet equipped with 5 mm ����C cryogenic probe. While relative configuration of the polyketide mandelalides was established after extensive J-coupling and NOE analysis, quantitative ROESY and RDC measurements were also explored before the absolute configuration was accomplished by chemical degradation and comparison with standards. The application of DOSY, a greatly under-appreciated technique in natural products research, led to the identification of new rubrolide analogues, compounds with moderate antibacterial properties from the new species Synoicum globosum. Finally, relative and absolute configuration of new and known unstable amino alcohols from two Pseudodistoma species was based on J-coupling analysis and application of the Mosher method. / Graduation date: 2013