Electrochemical copolymerization of a binary mixture of pyrrole and 2-amino-4-phenylthiazole on platinum electrode in acid medium was carried out. The kinetic parameters were calculated using ex situ microgravimetric and electrochemical data. The experimentally obtained kinetic equations were R-P,R-W = k(W) [acid](1.16) [monomer](1.85) from microgravimetric data and R-P,R-E = k(E) [acid](1.1) [monomer](1.9) from the values of the anodic current density using cyclic voltammetry technique. The apparent activation energy was calculated by the two techniques and is found to be 32.55 and 29.6 kJ/mol from microgravimetric and electrochemical data respectively. The monomer reactivity ratios (r(1) and r(2)) were calculated according to Fineman-Ross method and the copolymer structure was determined from the obtained data, which is found to be a block copolymer structure. The applications of the prepared copolymer as corrosion protection of mild steel in acid medium are studied. (c) 2006 Wiley Periodicals, Inc.