Disclosed herein is a method comprising reacting a phenolphthalein material and a primary hydrocarbyl amine in the presence of an acid catalyst to form a reaction mixture comprising 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, wherein the phenolphthalein material comprises greater than or equal to 99 weight percent phenolphthalein, based on the total weight of the phenolphthalein material; quenching the reaction mixture and treating the quenched reaction mixture to obtain a first solid. The first solid is purified by a combination of techniques to produce a solid comprising 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine with sufficient purity to be used as a monomer in the synthesis of clear polymers.