A large number of substrates have hitherto been employed in the Belousov-Zhabotinsky (B-Z) oscillatory system in pure aqueous medium. A systematic study of aromatic bromate oscillators is limited by solubility problem relating to the compounds and the brominated derivatives. The use of aqueous-organic mixed media for the oscillatory study is found to be highly useful for the study of water insoluble substances. A comparative study of the oscillatory behavior of gallic acid as substrate in pure aqueous as well as in a number of mixed media have been made in order to ascertain the suitability of mixed media in oscillatory systems. The alteration of oscillatory characteristics in the presence of organic solvent can be understood in terms of the Field-Koros-Noyes (FKN) mechanism. The oscillatory behavior of seventeen new substrates in the ferroin-catalyzed bromate system in 20% (v) acetonitrile is also presented and discussed in this communication. The reactivity of structurally related substrates has been correlated to the structure in terms of the relevant oscillatory parameters. The use of aqueous-organic mixed media in oscillatory systems would enable the investigation of new classes of substrates since getting them into the solution phase would no longer be a limitation.