This study investigates the regularities of coaction in multicomponent inhibitive mixtures and presents an analytical approach for optimizing their composition. A series of organic ligands of different nature, including set of amino acids, polyhexamethylene guanidine (PHMG), polyhexamethylene biguanide (PHMB) has been investigated as green and environmentally friendly complexing type corrosion inhibitors for the protection of steel. The preconditions and regularities of the film formation processes for the polymerization type inhibitors has been demonstrated using diphenylamine—Fe system. The influence of the additives of different nature, both individually and within inhibitive mixtures, and solution composition on phase layer formation was analyzed through gravimetric corrosion tests, polarization measurements, and surface characterization techniques, including scanning electron microscopy and atomic force microscopy methods in conjunction with extensive theoretical modeling. The findings highlight key mechanistic factors affecting electrochemical behavior and the complexing type inhibitor performance, such as ligand-metal complex stability and solubility, that may be used as predictors for selecting promising additive during the development of multicomponent mixtures. Additionally, the study demonstrates the potential for synergistic effects within binary inhibitor systems, exemplified by the NaNO2-PHMB mixture, which exhibited superior corrosion protection. These insights contribute to the rational design of novel corrosion inhibitors by integrating theoretical modeling with experimental validation.