Resonance is a fundamental chemistry concept first introduced to students in General Chemistry I (GCI), reintroduced in Organic Chemistry I (OCI), and then utilized throughout other higher-level chemistry courses. Student difficulties with resonance are well documented. Instruction is one potential source of student difficulties. What instructors choose to expose students to and how they choose to expose students to concepts related to resonance is influenced by instructors' intentions for learning. As a first step in understanding and addressing the difficulties students encounter when learning about resonance, we qualitatively examined what instructors intend for their students to understand about and do with resonance in the courses in which it is first introduced, GCI and OCI. The instructors we interviewed identified eleven critical features of resonance that they deemed important for students to learn about. We found that GCI and OCI instructors in this study identified many of the same critical features of resonance. However, there were differences in what they expected students to know about and do with those critical features. GCI and OCI instructors also identified critical features unique to their courses. Overall, while discussing the critical features, the instructors tended to emphasize an operational "versus" conceptual understanding of resonance, which may partially explain students' focus on "using" resonance instead of understanding it, as has been reported previously in the literature. The instructor-identified critical features presented herein have important implications for teaching and learning, as instructors' perceptions determine what they expose their students to during instruction and ultimately influence what students have the possibility to learn about resonance.