This paper reports the synthesis and investigation of a polymer composite based on poly(4-styrenesulfonic acid) (PSSA) and polyaniline (PANI) directly obtained in an aqueous PSSA medium, with improved conductivity and solubility in polar solvents. The oxidative polymerization reaction of aniline takes place in-situ with PSSA as protonating agent. The synthesis was tested at three PSSA/PANI molar ratios, an intense green colored aqueous composite solution being obtained in each case. For comparison purposes, commercially available polyaniline and PSSA were also investigated. PSSA-PANI composites, PANI and PSSA were investigated through thermal analysis, Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy. Thin films of PSSA/PANI complex were spin coated on glass substrates which were further investigated through Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Also, thin films of PSSA-PANI were deposited on interdigitated electrodes for dielectric measurements.