The interaction of nickel(II) with halogenazomercaptophenols (HAMPs) {1-(5-bromo-2-pyridylazo)-2-hydroxy-4-mercaptophenol and 1-(5-iodo-2-pyridylazo)-2-hydroxy-4-mercaptophenol} in the presence of aminophenols (APs) 2,6-bis(N,N-dimethylaminomethyl)-4-methylphenol and 2,6-bis(N,N-dimethylaminomethyl)-4-ethylphenol was studied by the extraction-photometric method. The charge of the resultant complexes was determined by the methods of ion electromigration and electrophoresis on paper. Colored complexes proved to be anions. Upon introduction of the aminophenols into the system the anionic complexes passed into the organic phase in the form of mixed-ligand complexes (MLCs). A single extraction with chloroform provided a 97.1–98.9% yield of nickel(II) in the form of an MLC. The optimal range of acidity of the medium, corresponding to a maximal and constant absorbance, was pH opt 2.4–6.5 (рH form 0.7–8.4). The maximum absorbance was reached within 8–12 min. The optimal condition for the formation and extraction of these compounds were identified as HAMP concentration of (1.12–2.34)×10 –3 M and the AP concentration of (6.3–8.4)×10 –4 M. A 20-fold increase in the volume ratio of the aqueous to organic phase did not affect the completeness of the extraction. Light absorption was at a maximum at 605–648 nm. In the composition of the MLCs, there was one mole of HAMP and AP each per mole of nickel. Using the Nazarenko method, it was found that Ni 2+ is the complexing form of nickel. The number of protons it displaced from one H 2 L molecule turned out to be equal to 2. The performed calculations showed that the MLCs do not polymerize in the organic phase and occur in the monomeric form (γ = 0.94–1.07). The results of studies on the formation and extraction of MLCs of Ni(II) with HAMP and AP and the physicochemical and analytical characteristics of these compounds served as a basis for the development of new techniques for the extraction-photometric determination of Ni(II) in wastewater, bottom sediments, crude oil, and petroleum products of Baku.