In- situ polymerizations were carried out in the presence of Al2O3, SiO2, and red mud ( RM) ( host materials) to synthesize poly( 2- halogenaniline)= Al2O3, poly( 2- halogenaniline)= SiO2, and poly ( 2- halogenaniline)= red mud composites. The 2- halogenanilines were polymerized without guest materials under the same conditions to compare the properties of the product with those of the composites. Homopolymers and composites were characterized by FT- IR and UV- vis spectroscopies, thermogravimetric analysis ( TGA), scanning electron microscopy ( SEM), X- ray diffraction spectroscopy, magnetic susceptibility, and conductivity measurements. The inclusion of either of those monomer units in the resultant composites was confirmed by FT- IR analysis. The properties of the composites changed depending on the type of host materials. Thermal stability of materials follows the trend according to their residual amounts at 800 degrees C of Al2O3 > RM > SiO2. The enhancements in thermal behaviors of poly( 2- halogenanilines) were studied in the presence of host materials ( RM, SiO2, Al2O3). SEM revealed interesting morphological features of the composites prepared using various inorganic materials and monomers. The analyses indicated typical structural differences between RM, SiO2, Al2O3, and poly( 2- halogenanilines). Magnetic susceptibility measurements revealed that the composites with SiO2 and Al2O3 have diamagnetic properties, whereas composites in the presence of RMshow paramagnetic conductivity mechanism. The conductivities of composites synthesized using three different materials were measured by a four- probe technique. The presence of Al2O3, SiO2, and RM affected the conductivities of pure polymers.