Compared to Anglo-American instructional design, European Didaktik has focused much more on content and relevance. This presentation will address why, what and how to teach in and about chemistry, as an example of a school subject. It will elaborate on concepts such as disciplinary literacy, powerful knowledge, Bildung, sustainability education and didaktik models (Sjöström, 2019; Sjöström, Eilks & Talanquer, 2020), as well as on their interrelationships. The goal is to explain what can be meant with powerful (chemical) knowings and eco-reflexive Bildung, as well as the characteristics of didaktik models aiming at those two. Eco-reflexive Bildung-oriented chemistry/science education should, in addition to (a) transformative subject knowledge, emphasize both (b) scientific processes – NOS (Nature of Science) – and (c) societal contexts – STSE (Science-Technology-Society-Environment) (Sjöström, Eilks & Zuin, 2016). In practice, this would mean including more philosophical, ethical and socio-political perspectives in chemistry/science education, and the focus should be on problematization, understanding uncertainties and balancing the benefits and risks of science and technology. In addition to these three legs, Hodson (2003) has suggested socio-political actions as a fourth leg. It is about promoting students’ critical and active engagement in socio-scientific problems and those often involves complex environmental and health issues. In the presentation, corresponding didaktik models – and especially such focusing socio-chemical issues, will be elaborated on. This will be done based on different curriculum ideas as well as philosophical ideas. Recently, Carlgren (2020) problematized the related concept of powerful knowledge and instead suggested powerful knowings. This concept emphasizes that disciplinary knowledge is embedded in actions. It is about “knowledge-as-a-means-for-cultivation-of-human-powers” (p. 324). The presentation will highlight ideas about relevant, transformative and powerful (chemical) knowings for sustainability and related educative practices. Examples will be given from two ongoing PhD projects (Clucas and Yavuzkaya).