Thinking like a designer involves different kinds of abilities and competences in different fields of knowledge: conceiving, planning and making products (Buchanan 1999). Those are cognitive processes manifested in design action. Designers are used to deal with complex problems, and by generating diverse high-scoring solutions, analysing and evaluating them in order to gradually improve them (Dorst 2006). This is what students should be enabled for and what the so-called key competences are all about: dealing with complex real-life problems by analysing and evaluating them in order to act solution-oriented and responsible. Design Thinking realizes what is recommended theoretically in constructivist theory. Especially learning through experience and complex problem solving among other aspects are met in Design Thinking and can be employed at all age groups, e.g. extensive experiences at the K12 program at the d.school in Stanford, USA. Design Thinking is a constructivist learning design, because of its qualities in training certain skills, which are predispositions for a constructive way of learning: motivation for exploration, openness for new ideas, creative thinking and other metacognitive competences (Noweski 2012). In a Design Thinking context as described in the phases below, such predispositions are met to ensure 21st century skills development. Students are motivated for exploration, trust is build up between student and teacher to give confidence for self-exploration, and team competences are fostered to express ones opinion and share knowledge. A formalised process guides the teacher towards constructivist learning. Design Thinking can be realised in short sessions integrated in a highly specialized A Level biology class, as in interdisciplinary full project weeks