Structural and electronic transitions in polyaniline (PANI) matrix due to the presence of nickel-nanoclusters (PANI-Ni) were investigated via UV-Vis spectroscopic measurements. The obtained results indicate that there exist two populous packets of polaron (located at 872 and 973 nm) in both PANI and PANI-Ni. Due to the presence of nickel-nanoclusters, a quinoid-to- aromatic conversion was intensively happened and evidenced by: i- the existence of a steadily increasing absorption tail; ii- degeneration of a ground state of polarons of PANI and split into three exciting states with three sublevels of energy. Consequently, the polaron lattice of PANI was revealed in a higher degree of electron delocalization in PANI-Ni.
