Naturally occurring polyphenol(condensed tannin)-phenol-formaldehyde copolymer matrix based cation exchange resins have been successfully used as a solid catalyst (in H+ ion form) in the inversion of sucrose and hydrolysis of methyl acetate. Apart from the normal advantages of the solid catalysts over the acid catalysts in the solution phase, the values of the activation energy, entropy, and enthalpy of activation of the reactions involved reveal that the resins prepared acted as a catalyst with characteristics comparable to those of the commercially available resins based on a styrene-DVB matrix. The resins have also been successfully used for softening of hard water and enrichment of metal ion concentration from very dilute solutions.