Abstract: A melt processible Polyether Ether Ketone (PEEK) polymer with novel end-group structure is synthesized electrophilically using Methane Sulfonic Acid containing Methane Sulfonic Anhydride or Phosphorous Pentoxide. The product so obtained shows controlled structure with elimination of reactive end group like —COOH and is therefore melt processible by conventional techniques and exhibits high thermal and mechanical properties making it useful high temperature engineering and specialty plastics. It can be extruded into a rod, film and can also be molded into commercially useful products.