Investigation of the photocatalytic activity of BaTiO₃, a perovskite wideband gap semiconductor has been done in comparison with a widely used photocatalyst TiO₂ for the degradation of 4-chlorophenol (4-CP), 4-chloroaniline (4-CA), 3,4-dichloronitrobenzene (3,4-DCNB), and 2,4,5-trichlorophenol (2,4,5-TCP). BaTiO₃/TiO₂ nanoparticles were prepared by gel-to-crystalline conversion method. BaTiO₃ has exhibited better catalytic efficiency and process efficiency compared with TiO₂ in most of the cases. The present research focuses mainly on two aspects: first the photocatalytic activity of BaTiO₃, as there are very few reports in the literature, and second the reactivity/orientation effects of substituent groups of the pollutant molecules on the degradation rate. The above chloroorganic compounds have at least one chlorine substituent in common, along with other functional groups such as −OH, −NH₂, and −NO₂. Furthermore, the effect of electron acceptors and pH on the rate of degradation is presented. The reactions follow first-order kinetics. The degradation reaction was followed by UV−vis, IR, and GC-MS spectroscopic techniques. On the basis of the identification of the intermediates, a probable degradation reaction mechanism has been proposed for each compound.