An interesting interfacial redox method is developed for the preparation of Au nanoparticles of various shapes in organic medium using Au seeds in aqueous medium without using phase-transfer reagent. The conversion, stabilization, and the transfer of gold nanoparticles to the organic phase is accomplished using the reducing and solubility properties of poly(o-methoxy aniline) in chloroform. The preparatory method is simple, and the Au nanoparticles are free from excess oxidant and external stabilizer. The characterizations of the metal nanoparticles are made using transmission electron microscopy, UV-vis spectra, electron diffraction and energy-dispersive X-ray techniques. Au nanoparticles of various shapes, for example, hexagonal, pentagonal, triangular, rod-shaped, etc. are produced together. A mechanism of the formation of differently shaped nanoparticles is proposed from catalytic reduction of Au(3+) ion by POMA on the Au seed surface followed by the growth of nanoparticles from the exposed Miller planes of seed surfaces.