This work develops a dynamical, information-based cosmological model in which dark energy emerges not as a fixed vacuum constant but as a geometric response of spacetime to the universe’s increasing structural and informational complexity. The central proposal introduces a time-dependent cosmological term Λ(t) = α · dC/dt where C(t) quantifies the total relational complexity of the universe, including contributions from classical matter organisation, hierarchical structure formation and quantum entanglement. As the density of relational structure grows, the spacetime manifold expands to accommodate this increase, producing an effective topological pressure that appears observationally as dark energy. The model provides a concrete dynamical mechanism absent in ΛCDM, addressing longstanding challenges such as the cosmological constant problem, the coincidence problem and the lack of an evolutionary explanation for late-time acceleration. It predicts testable deviations from ΛCDM at intermediate redshifts, especially where the dominant sources of dC/dt shift from classical structure formation to microscopic, entanglement-driven complexity. Dark Energy as Topological Pressure integrates naturally into a broader information-centric paradigm developed by the author. In the companion paper Information-Centric Cosmogenesis (ICC), universes arise from minimal informational structures called kernels. Within this wider cosmogenetic framework, DETP describes how kernel-defined relational dynamics continue to shape spacetime long after the universe’s ignition, linking the growth of structural complexity to the observed acceleration. This interpretation also aligns with two complementary theoretical principles formulated by the author: • The Kernel Ontology Principle (KOP) – which views spacetime geometry as the external expression of a minimal relational kernel.• The Energy–Information Continuity Hypothesis (EIK) – which proposes that informational change carries an energetic cost, offering a microphysical basis for the Λ(t) behaviour derived in DETP. Together, Cosmogenesis, KOP, EIK and DETP form a unified informational framework in which physical law, cosmic expansion, dark energy and cosmological reproduction arise from the evolving relational microstructure of the universe. This work outlines observational signatures, theoretical implications and pathways toward a quantitative information-based cosmology connecting microscopic information dynamics with large-scale cosmic acceleration. This work belongs to the Information Kernel Framework (IKF) collection. The complete set of foundational papers, including ontology, informational dynamics, cosmogenesis and complexity-driven cosmology, is available in the official IKF dataset at: https://doi.org/10.5281/zenodo.18437199 For feedback or questions, contact: k.havrankova@proton.me