The relative contributions of aromaticity, conjugation and functional group chemistry to specific ultraviolet (UV) absorbance (SUVA), reactions of chlorine with natural organic matter (NOM) and the formation of disinfection byproducts (DBPs) was investigated using model compounds. Conjugation was found to contribute significantly to SUVA, which does not support the assumption that SUVA is simply a measure of aromaticity. Resorcinol, ferulic acid and salicylic acid produced high concentrations of chloroform when chlorinated, which suggests that structures similar to these in NOM may be responsible for the production of chloroform when natural waters are chlorinated. The differential UV spectra of the model compounds were much more complex than NOM. The relationship between differential UV absorbance and chloroform production of the model compounds and NOM differed. This suggested that structures that contribute significantly to the production of chloroform in NOM may not contribute significantly to the differential UV absorbance, and vice versa. High performance size exclusion chromatography of the compounds after chlorination showed peaks attributed to unknown DPBs common to most of the model compounds. Includes 27 references, tables, figures.