Protonated species of the nucleobase cytosine (C), namely the monoprotonated CH+ and the hemiprotonated CHC+, were used to obtain four charge-transfer complexes of [Ni(dmit)(2)] (dmit: 1,3-dithiole-2-thione-4,5-dithiolate). Diffusion methods afforded two semiconducting [Ni(dmit)(2)](-) salts; (CH)[Ni(dmit)(2)](CH3CN) (1) and (CHC)[Ni(dmit)(2)] (2). In salt 1, the [Ni(dmit)(2)](-) ions with a S=1/2 spin construct a uniform one-dimensional array along the molecular long axis, and the significant intermolecular interaction along the face-to-face direction results in a spin-singlet ground state. In contrast, salt 2 exhibits the Mott insulating behavior associated with uniform 1D arrays of [Ni(dmit)(2)](-), which assemble a two-dimensional layer that is sandwiched between the layers of hydrogen-bonded CHC+ ribbons. Multiple hydrogen bonds between CHC+ and [Ni(dmit)(2)](-) seem to result in the absence of structural phase transition down to 0.5K. Electrooxidation of [Ni(dmit)(2)](-) afforded the polymorphs of the [Ni(dmit)(2)](0.5-) salts, (CHC+)[{Ni(dmit)(2)}(0.5-)](2) (3 and 4), which are the first mixed-valence salts of nucleobase cations with metal complex anions. Similar to 2, salt 3 contains CHC+ ribbons that are sandwiched between the 2D [Ni(dmit)(2)](0.5-) layers. In the layer, the [Ni(dmit)(2)](0.5-) ions form dimers with a S=1/2 spin and the narrow electronic bandwidth causes a semiconducting behavior. In salt 4, the CHC+ units form an unprecedented corrugated 2D sheet, which is sandwiched between the 2D [Ni(dmit)(2)](0.5-) layers that involve ring-over-atom and spanning overlaps. In contrast to 3, salt 4 exhibits metallic behavior down to 1.8K, associated with a wide bandwidth and a 2D Fermi surface. The ability of hydrogen-bonded CHC+ sheets as a template for the anion radical arrangements is demonstrated.