General chemistry is the first undergraduate course in which students further develop their understanding of fundamental chemical concepts. Many of these fundamental topics highlight the numerous conceptual interconnections present in chemistry. However, many students possess incoherent knowledge structures regarding these topics. Therefore, effective assessments are needed to identify these interconnections. The use of concept-mapping and think-aloud interviews to investigate the knowledge structures of undergraduate organic chemistry students' regarding bonding concepts is the focus of this research study. Herein, we spotlight the bonding concepts of electronegativity and polar covalent bonds. In essence, the study found that understanding of electronegativity was weak among students with low concept map scores (LS students) compared to students with high concept map scores (HS students). Additionally, several common misconceptions of electronegativity were revealed through student interviews. An examination of LS student interviews further revealed that a lack of understanding of electronegativity led to a misunderstanding of polar covalent bonding. The think-aloud interviews were a reflection of the connections students made with the concepts of electronegativity and polar covalent bonding in their concept maps. Implications for the chemistry curriculum are also presented.