Abstract
Background Although sustainability is increasingly emphasized in science education following the Sustainable Development Goals (SDGs), its integration into upper secondary chemistry often remains thematic rather than structurally embedded in chemical reasoning.Purpose This study investigated whether redesigning a compulsory Grade 11 ‘Green Chemistry’ chapter through an SDG-aligned, systems-oriented instructional framework enhances students’ sustainability competencies and structural systems reasoning compared to textbook-based instruction.Sample Participants were 96 Grade 11 students from a public secondary school in Kazakhstan, assigned to experimental and control groups based on intact classrooms.Design and methods A quasi-experimental pretest – posttest control group design was implemented over six weeks. The experimental condition embedded green chemistry principles within structured systems modeling tasks, while the control group followed the standard curriculum. Outcomes were assessed using a validated Sustainability Competency Index and a rubric-based Systems Mapping Task, with analyses controlling for baseline differences.Results Students exposed to the systems-oriented redesign demonstrated substantially greater gains in sustainability competencies and systems reasoning than those receiving traditional instruction. Systems reasoning performance was positively associated with sustainability competency development.Conclusion Findings indicate that restructuring instructional architecture – rather than expanding curricular content – can meaningfully support sustainability-oriented learning within standardized secondary chemistry contexts.