The addition of organic and organo-metallic chromophores to TiO2 lowers the absorption threshold of light to the visible range. Thus dye sensitized TiO2 represents a promising system for use in solar energy conversion devices. The electron transfer characteristics of a dye sensitized TiO2 surface depend on the bonding configuration of the anchor group. Catechol is a small organic molecule frequently used to anchor large chromophores to the TiO2 surface. We have thus utilized angle resolved ultraviolet photoemission spectroscopy (ARUPS) to determine the bonding structure of catechol on the surfaces of the rutile and anatase polymorphs of TiO2. For catechol on rutile (110), Scanning Tunneling Microscopy studies show a densely packed 2×1 monolayer; the proposed adsorption geometry is similar to that of carboxylic acids on rutile (110). Photoemission data support a bidentate adsorption structure. The presence of lateral interactions in the densely packed monolayer is also inferred.