The present work describes a remarkable synthetic interest of semiconducting core-shell nanocomposites (CSNCs) contained aluminum oxide. Al2O3@poly(aniline -co- o-phenylenediamine) (Al2O3@PANI-o-PDA) CSNCs were fabricated by fivefold molar ratio of the appropriate moieties with various quantities of gamma-Al2O3 by oxidative polymerization. The formation of the Al2O3@PANI-o-PDA CSNCs was confirmed by spectral characteristics. The nanocomposite core-shell feature was found cores thickness 38 nm and shells thickness 41-44 nm. The recorded sigma(dc) is 2.9 x 10(-8)-1.45 x 10(-7) ohm(-1) m(-1) being in the range of semiconductor materials at room temperature and increases with increasing temperature. The newly fabricated materials were investigated as antimicrobial agents. The setup presents a facile, cheap, novel and beneficial methodology to develop novel CSNCs acquiring the required numerous functionality.