The reaction between 1,10-phenanthroline (phen) and a nitric acid solution of platinum was studied. It was shown that, in contrast to the earlier studied reactions with pyridine and piperazine, no solid phases were formed by the salts of anionic platinum(IV) nitrato complexes with the phenanthrolinium cation in this case due to their high solubility. The new molecular platinum(IV) complex containing 1,10-phenanthroline [Pt(phen)(NO3)4] (1) was prepared upon long-term exposure. The salt (phenH)4(NO3)2[Pt(NO3)6] (2) was synthesized by the reaction between phenanthrolinium dinitrate (phen · 2HNO3) and the salt (Bu4N)2[Pt(NO3)6] in acetonitrile with a high yield. The crystal structure of complexes 1 and 2 was characterized by X-ray diffraction. Complex 2 was studied by IR spectroscopy, thermal analysis, and solid-state magic-angle spinning (SS-MAS) 195Pt NMR spectroscopy. The results of this work could be used to develop the synthesis of new platinum complexes and for the preparation of platinum-containing heterogeneous catalysts.