This paper investigates the self-similar structure of a class of nonlinear diffusion systems with coupled dynamics, where crossinteractions between components substantially affect the long-time evolution and the formation of singular regimes. We focus on the qualitative and quantitative description of solution profiles through scaling transformations that reduce the original parabolic system to an associated self-similar problem. By combining comparison principles with nonlinear splitting techniques, we derive constructive upper and lower estimates for weak solutions and identify parameter regimes that distinguish finite-time blow- up from global-in-time behavior. The asymptotic analysis reveals the emergence of compactly supported self-similar profiles, the localization mechanism driven by nonlinear diffusion, and the role of coupled source terms in shaping the free-boundary propagation. In addition, we establish asymptotic expansions near the interface and describe the limiting selfsimilar attractors governing the solution dynamics. The obtained results provide a unified framework for assessing the interplay between nonlinearity, coupling, and scaling, and they support reliable numerical verification through finite-difference discretizations and iterative solvers.