The structure and bonding in 2-diazo-4,6-dinitrophenol (DDNP) is discussed on the basis of quantitative molecular orbital (MO) calculations at the density functional theory (DFT) level using the natural bond orbital analysis (NBO). Qualitative valence bond theory (VB) was used to generate an increased VB structure for DDNP. The increased-valence structure is better in accordance with the computed and observed (X-ray) geometry than is the NBO analysis.