The present invention pertains generally to the field of therapeutic compounds, and more specifically to crystalline forms of 4-(5-(4,7-dimethylbenzofuran-2-yl)-1,2,4-oxadiazol-3-yl)benzoic acid (referred to herein as "BHBA-001"), which, inter alia, is a (selective) retinoic acid receptor beta (RARβ) (e.g., RARβ2) agonist. The present invention also pertains to pharmaceutical compositions comprising such crystalline forms, and the use of such crystalline forms and compositions, both in vitro and in vivo, to (selectively) activate RARβ (e.g., RARβ2), to cause or promote neurite development, neurite outgrowth, and/or neurite regeneration, and in the treatment of diseases and conditions that are mediated by RARβ (e.g., RARβ2), that are ameliorated by the activation of RARβ (e.g., RARβ2), etc., including, e.g., neurological injuries such as spinal cord injuries.