For an educational reform to succeed, teachers need to adjust their perceptions to the reform's new curricula and strategies and cope with new content, as well as new teaching and assessment strategies. Developing students' scientific literacy through context-based chemistry and higher order thinking skills was the framework for establishing a new chemistry curriculum for Israeli high school students. As part of this endeavor, we developed the "Taste of Chemistry" module, which focuses on context-based chemistry, chemical understanding, and higher order thinking skills. Our research objectives were (a) to identify the challenges and difficulties chemistry teachers faced, as well as the advantages they found, while teaching and assessing the "Taste of Chemistry" module; and (b) to investigate how they coped with teaching and assessing thinking skills that include analyzing data from graphs and tables, transferring between multiple representations and, transferring between chemistry understanding levels. Research participants included eight teachers who taught the module. Research tools included interviews, classroom observations, teachers-designed students' assignments, and developers-designed students' assignments. We documented different challenges teachers had faced while teaching the module and found that the teachers developed different ways of coping with these challenges. Developing teachers' assessment knowledge (AK) was found to be the highest stage in teachers' professional growth, building on teachers' content knowledge (CK), pedagogy knowledge (PK), and pedagogical-content knowledge (PCK). We propose the use of assignments designed by teachers as an instrument for determining their professional growth.