Electrochemical polymerization of aniline has been studied using real-time spectroelectrochemical experiments conducted concurrently with potentiodynamic scans in a nitric acid electrolyte with its pH adjusted to 0.50. Two-dimensional correlation spectral analysis and subsequent extraction of pure component spectra as well as their relative concentration profiles from complex spectroelectrochemical data employing the alternating least-squares regression iteration-based self-modeling curve resolution method led to positive identification of intermediate species. A conclusion was reached on the polymerization reaction mechanism based on these intermediate species and how their concentrations increased or decreased during the potential scans. The mechanism thus concluded represents a summary of a current understanding of the aniline polymerization reaction.