The use of organic additives is widespread in the manufacturing of thin films by electrochemical deposition. Common additives like saccharin (SAC) were used as leveling and brightening agents in the cobalt-iron deposits. In the present work, effects of additives molecular structure on the CoFe deposits from sulfate electrolytes at pH 3 were investigated. Plithalimide (PHTA) and a new additive (OAS) were tested like organic additives to understand the influence of different functional groups of these compounds. The composition and the morphology of the binary alloy were examined by SEM. The corrosion properties were characterized by voltammetry. The main results revealed that the presence of the sulfonamide in the structure of organic additives does not play the role in brightening and leveling agent, but this function seems to be important for CoFe deposit corrosion resistance even if all additives change the deposit corrosion resistance properties. Moreover, the complexation between the iron ion and the organic additive seems to be affected by the presence of the carbonyl group.