Polymerization from neutral red can be performed in acidic and weakly basic aqueous solution and two types of stable and electrochemically active films can be produced. The film can be produced on glassy carbon, platinum, gold, and transparent semiconductor tin oxide electrodes. A two-layer modified electrode containing organic and inorganic films can also be prepared via poly(neutral red) and cobalt hexacyanoferrate films; the cobalt(II) hexacyanoferrate film is electrocatalytically active for the oxidation of NADH in 0.1 M RbNO3 aqueous solution and the electrocatalytic oxidation current develops from the anodic peak of the redox couple. The electrocatalytic reduction of BrO3 − and IO3 − directly by poly(neutral red) in a strong acidic aqueous solution shows that the electrocatalytic reduction activity is obviously pH dependent in a pH range from 1.0 to 4.0. The iodic electrocatalytic oxidation current appears when I− is produced from the electrocatalytic reduction of IO3 − by poly(neutral red). The catalytic decomposition of H2O2 into H2O and O2 by I− can be initiated via the electrocatalytic reduction of IO3 −. The electrocatalytic reaction was also performed using the rotating ring-disk electrode method. The polymer film also shows activity towards the electrocatalytic reduction of oxygen and nitrite in aqueous solution. The electrochemical quartz crystal microbalance technique and cyclic voltammetry were used to study the in situ growth of poly(neutral red) film. The polymer films were obtained and transferred to various solutions between pH 0.5 and 14. The formal potential plotted against pH has a slope −66 mV/pH.