The optical and hydrodynamic properties of aqueous and aqueous salt (NH4Cl) solutions of poly(N-vinylcaprolactam) (PVCL) and two DNA samples (M = 107, 1.5 × 107 Da) in the presence of sulfonated lutecium and scandium diphthalocyanines were investigated. The results of the spectrophotometric titration performed in the range λ= 330-1100 nm under different ionic conditions indicated the formation of complexes between the polymers and the dyes. The parameters of the equilibrium binding of the dyes with the polymers were calculated in the framework of the Scatchard model. The polymer complexes with dyes were prepared taking into account the calculated parameters, and the intrinsic viscosities [η] proportional to the specific volume of a molecule in a solution were measured. It was found that, in the systems containing DNA in a 0.001 M NH4Cl solution, the dye molecules are involved in cooperative binding with the DNA molecules and the size of the complexes decreases (with an increase in the fraction r of bound dye molecules) as compared to the size of a free DNA molecule.