A mixed-method educational research study was conducted to evaluate the use of a series of online histopathology modules by students at two levels in a professional veterinary medical program. The materials were hypothesized to support student learning of histopathology concepts by facilitating "dual coding" of the content, since they provide both visual and verbal information. Second- and fourth-year professional veterinary students were surveyed about their perceptions of the effectiveness, efficiency, and appeal of the online modules. A historical comparison of final grades in the second-year Pathology course was conducted to evaluate the impact of the materials on academic outcomes. Think-aloud interviews were conducted with the fourth-year students in which the researcher observed the students interacting with the materials and asked them to "tell me what you're thinking as you use the modules." Survey results show that the only area in which the two student groups quantitatively rated the materials differently was their perception of how the materials complemented their learning. In contrast, the qualitative data indicate that advanced students used and perceived the materials differently, perhaps because of their greater metacognitive skills and pre-existing knowledge. We concluded that these findings can be attributed to the manner in which students approached the materials: the fourth-year students felt the materials were less relevant because they did not directly correspond to cases they were seeing, while the second-year students appreciated their relevance to topics in the Pathology course. There was no significant difference in final exam performance for the group of students that used the supplemental online modules and the prior four years' classes, who did not have access to the materials. Overall, this study demonstrated that it is possible to create a set of materials to be used by multiple audiences, provided the needs of each group are taken into consideration during the design process.