Poly (aniline-co-pyrrole) (PANI-co-PPy) with variable loadings of copper alumina (Cu-Al2O3) nanoparticles were synthesized by benign in-situ chemical oxidation polymerization. The structural, thermal transition and morphological interpretations were made with Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and high-resolution transmission electron microscope (HR-TEM). The electrical properties such as AC conductivity and dielectric measurements were performed at room temperature to verify their application in developing new electronic devices. The arrangement of nanoparticles in the copolymer and the synergistic interaction in the polymer matrix was deduced from FT-IR and XRD. HR-TEM indicates the nanosized uniform dispersion of filler in the copolymer. DSC revealed a reduction in the flexibility of polymer with an increase in glass transition temperature of copolymer composites. AC conductivity measurement manifested an increased hopping of charge carriers in nanocomposites when compared with pristine PANI-co-PPy. Dielectric properties were maximum for copolymer with 5wt.% Cu-Al2O3. The increase in dielectric properties of copolymer nanocomposites confirmed the efficient packing density of nanofiller within the polymer. Excellent gas sensing traits were observed for copolymer nanocomposites due to the electron transfers existing between PANI-co-PPy and ammonia gas. The magnificent material properties make (PANI-co-PPy)/Cu-Al2O3 nanocomposites, a promising contender for developing nano-electronic devices.