(54598) Bienor is km-sized centaur located between the orbits of Saturn and Uranus ( AU, AU, ). This body has been extensively studied using various observational techniques. Recent studies reveal disparities in size between photometric measurements and thermal models. Furthermore, it exhibits a long-term variation in its absolute magnitude that exceeds what would be expected based on a hydrostatic equilibrium shape. This has prompted suggestions that Bienor could be a close-in or contact binary, although this remains an unresolved question. To address this issue, we have organized multiple campaigns in recent years to observe stellar occultations by Bienor and acquire rotational light curves. Additionally, we have developed software to simulate synthetic rotational light curves based on its orbital properties and 3-D shape models, facilitating comparisons with actual rotational light curves. In this study, we present the findings from four positive multichord occultations that occurred in 2021, 2022, and 2023, along with the results of the comparison of rotational light curves.