Dialogic use of exemplars is effective in developing student understanding of assessment standards. However, limited studies have investigated how exemplar dialogues are conducted in the post-secondary context. To fill the gap, this teacher-research explores the characteristics of peer and teacher-student exemplar talk in three post-secondary classrooms and the challenges in the dialogic process. The participants involved 69 first-year post-secondary students, a critical friend and a teacher-researcher. Data analysis on selected dialogue excerpts, an open-ended survey, focus group interviews with the students, critical friend's commentary and a teacher-researcher reflective journal indicated two major issues: (i) students' lack of capacities to resolve socio-cognitive conflict in the peer dialogue; (ii) the dilemma of addressing students' immediate assessment needs and developing their long-term evaluative judgements in the teacher-student dialogue. Recommendations are made to tackle the challenges and to orchestrate productive exemplar dialogues.