The present invention relates to a process of cinnamates using polyaniline salts as catalysts. The present invention more particularly relates to a process for producing cinnamic esters by the direct esterification of cinnamic acid with aliphatic alcohols over polyaniline salts as catalysts. The process of esterification may be carried out by reacting cinnamic acid with aliphatic mono hydric alcohol in presence of catalyst, removing the catalyst by conventional methods. The ester can be isolated such as filtration followed by isolation of esters by conventional column chromatography using adsorbent such as silica gel and solvent such as chloroform, ethylacetate, hexane and mixture thereoff.