This study was conducted to investigate concept mapping as an instructional technique to help student designers tackle complex issues in instructional design. Specifically, this study focuses on three dimensions: perceived learning, collaborative learning, and usability. We examined how student designers perceived the use of Cacoo as a concept mapping tool in three different instructional design courses and how a concept mapping approach facilitated or constrained students' design process. The study participants were 24 graduate students enrolled in three different courses over the span of a year. Through quantitative descriptive analysis and qualitative coding, our data revealed students' overall positive perception toward Cacoo and demonstrated various means in which student designers successfully utilized the concept mapping approach to create external representations. We also provided implications for practitioners and recommendations for future researchers.