The synthesis of the thiophene analogs of the cardio‐selective β‐adrenergic blocking agents Practolol and “reversed” Practolol has been attempted starting from 2‐acetyl‐5‐bromothiophene. Although this synthesis worked for the second compound it was not possible to obtain the first one. From this and other results of this paper it can be deduced that the thiophene analog of Practolol must be an unstable compound.