In searching for effective ways to combine science/chemical education with EE/ESD, new didactic materials were designed and produced focussing on biogeochemical cycles and their connection to sustainable development. The materials were experimentally applied in 16 Greek schools under the newly introduced compulsory "school project" which offers an excellent opportunity for the development of EE/ESD projects. The effectiveness of the intervention was assessed on the basis of questionnaires including knowledge and attitude questions and considering several factors (students' performance/grades, sex, previous participation in EE/ESD programmes, parents' educational level, etc.). The results demonstrated a positive impact on students' knowledge not only on biogeochemical cycles, but also on aspects related to sustainable development. Similarly, several components of students' attitudes vis a vis the environment and sustainable development (e.g. "Action commitment", "Efficacy perception of personal action" and "Sustainable orientation of the positive attitude towards the environment") were influenced positively.