A novel polyaniline-fluoroboric acid-dodecylhydrogensulfate (PANI-HBF4-DHS) salt was directly synthesized via emulsion polymerization pathway. Aniline was oxidized to polyaniline salt by benzoyl peroxide in presence of sodium lauryl sulfate and fluoroboric acid. This polymerization pathway leads to incorporation of both acid group as well as surfactant group into the polyaniline chain as dopants. The polyaniline salt was characterized by Fourier transform infrared spectroscopy, electronic absorption spectroscopy, X-ray diffraction studies, scanning electron microscopy, elemental analysis, viscosity and conductivity measurements. PANI-HBF4-DHS salt is used as catalyst for the first time in various organic reactions such as Mannich-type reaction, Biginelli reaction, Pechmann reaction, esterification and carbonyl protection. The advantages of the PANI-HBF4-DHS salt are ease of preparation, easy handling, recovery, simple work-up, reusability and versatility. (c) 2005 Elsevier B.V. All rights reserved.