Styrenated oil, urethane oil, and oil modified alkyd resin were prepared by using castor oil in a different way. For this purpose, castor oil was initially subjected to an interesterification reaction with linseed oil, and the resulting intermediate was employed in the preparation of oil-based binders. Urethane oil and alkyd resin were obtained through the reactions of the interesterification product with toluene diisocyanate and phthalic anhydride, respectively. For the production of styrenated oil, thermally labile azo groups were inserted into the interesterification product and then this intermediate was reacted with styrene. Styrenated oil showed the best alkali resistance.