The rheological properties and phase-lag behavior of interpolymer complexes formed from sodium carboxymethylcellulose and polyacrylamide were investigated using an Anton Paar Modular Compact Rheometer under controlled temperature and frequency conditions. The study examined viscoelastic responses, dynamic viscosity, and their dependence on shear rate and angular frequency, complemented by potentiometric and conductometric analyses to assess complex formation. The complexes displayed pronounced shear-thinning (pseudoplastic) behavior, characteristic of entangled polymer chains, with decreasing viscosity under increasing shear rate. Both elastic and viscous moduli rose with angular frequency, reflecting strengthened material responses at higher deformation rates. The damping factor exhibited frequency-dependent variation, decreasing at low frequencies (indicating elastic dominance) and slightly rising at higher frequencies (shifting toward viscous behavior). No gel point was detected, signifying the lack of a fully cross-linked network. Complexation was optimal at a 60/40 sodium carboxymethylcellulose / polyacrylamide ratio, evidenced by pH inflection and minimum conductivity due to ionic interactions and charge neutralization. These results demonstrate the rheological stability and tunability of sodium carboxymethylcellulose / polyacrylamide complexes, positioning them as promising materials for coatings, printing inks, and adaptive polymer applications.