The first results of nucleophilic substitution reactions performed in one step, starting from the nitrocobaltocenium cation, are presented. The nitrocobaltocenium ion reacts with water, alcohols, or primary amines, forming the corresponding monofunctionalized cobaltocenium cations. The substitution occurs with primary amines without further additives, whereas for water and alcohol as nucleophiles, additional strong bases like sodium hydroxide are required. Here, we discuss the synthesis and the role of sodium hydroxide. The new compounds are spectroscopically characterized by IR, H-1 NMR and C-13 NMR spectroscopy, as well as HRMS. The electrochemical behavior of different cobaltocenium salts is reported. Furthermore, molecular structures were obtained from the PF6 salts of azidocarbonylcobaltocenium, nitrocobaltocenium, and methoxycobaltocenium.