4,4′‐diisothio‐cyanostilbene‐2,2′‐disulfonic acid (DIDS) is a stilbene derivative with pleiotropic biological nature. DIDS not only affects the activity of several ion channels and transporters in mammalian cells, but also mediates cell survival and neurodegeneration. Recently, we and others have observed that DIDS could prevent cell damage in both in vivo and in vitro ischemia models. However, the mechanism underlying DIDS protection is not clear. In this study, we examined the role of the isothiocyanate group (SCN) as the functional moiety in the DIDS molecule and its effect on cell death. Using an in vitro ischemia model (IS) developed in our laboratory that uses organotypic brain slices and propidium iodide fluorescence as an assay for cell death, we compared the protective effect of several stilbene derivatives that have different numbers of SCN groups. Our data show that at 400 µM, DIDS and H2DIDS (both have two SCN groups) blocked IS‐induced cell death by 100%, SITS (with one STC group) blocked by about 50%, and DNDS (with no SCN group) had no effect. These results strongly support the idea that the rescue of cell death by DIDS is dependent on the presence of the STC moiety.