Mechanistic aspects of sorption of Rhodamine B and Methylene Blue by sulfonated coal have been investigated. The coal surface before and after sulfonation has been characterized with the help of cation-exchange capacity measurements and infrared (LR) spectroscopy. These studies indicate that sulfuric acid treatment not only incorporates a SO3H group on the coal surface but also oxidizes both aliphatic and aromatic fractions. The IR spectroscopy has been extensively applied to locate the active sites on the surface of the sorbent and the participating functional groups of the dye molecule. Graphical models of the sorbate-sorbent interaction have been proposed. These models are applied to explain the variation in the uptake potential of these dyes by sulfonated coal.