Resonance is a crucial concept in Organic Chemistry that enables both deriving chemical properties from molecular structures and predicting reactions by considering electron density distribution. Despite its importance for problem-solving and learning success, learners encounter various difficulties with this concept. Although prior research suggests that learners struggle to reason about resonance in problem-solving tasks, existing studies are often limited to singular contexts. Given that task approaches and reasoning are context-dependent, little is known about how learners use resonance across task contexts and which characteristics underlie productive concept use. To this end, a qualitative interview study was conducted, in which undergraduate chemistry students (N = 21), all beginners of Organic Chemistry, solved three organic case comparison tasks requiring the consideration of resonance. Through the analytical lens of the coordination class theory, we analysed the extent to which students used their representations of resonance structures, their task approaches, and the variety of resonance-related resource activation and connection in problem-solving across three different contexts. The results show that students' use of resonance is diverse across the contexts. It can be characterized by a complex interplay of multiple factors reflecting the multifold processes when considering resonance. However, some essential characteristics of productive concept use in problem-solving (e.g., the activation of resources across different granularity levels) could be deduced. Implications for supporting learners' use of resonance in problem-solving are discussed.