As predicted at the B3LYP/LANL2MB level of theory, the adsorption of tetraaza[14]annulene ligands (simple analogues of porphyrins and phthalocyanines) on single-walled carbon nanotubes is insignificantly influenced by the presence of aliphatic (methyl) or/and aromatic (benzo) substituents on the macrocyclic molecules. On the contrary, the adsorption dramatically increases in the case of metal (cobalt) complexes, resulting in substantial changes in their geometry and electronic structure. An increase in negative electrostatic potential at the exposed macrocycle side was found for the Co(II) complexes. It might give rise to an enhanced reactivity toward electrophilic agents, which, along with the strong adsorption predicted, is an encouraging prerequisite for the preparation of new hybrid carbon-nanotube-based catalysts.