Converting a first-term, accelerated summer organic chemistry course to a flipped format reduced the achievement gap in the flipped course and in the second-term traditional lecture course between Non-Repeaters taking an accelerated course to "get ahead" and Repeaters taking the course to "get back on track". The difference in final exam performance in the second-term course was nearly halved, the GPA gap in both courses was reduced, and the gap in passing rate for the second-term course was eliminated. First-generation students who took the first-term course in the flipped format experienced a final exam score boost in the second-term course regardless of repeater status. While most students responded positively to the flipped course structure, repeating students held a stronger preference for the flipped format. These findings provide guidance on how to create courses that promote equity, access, and retention of diverse students in STEM.