Catecholatostiboranes have emerged as useful Lewis acids in several applications. To better understand the factors that control the properties of these species, we examined the Lewis acidities of (o-C6Cl4O2)Sb(o-Tol)3 (2, Tol = tolyl) and (o-C6Cl4O2)Sb(p-Tol)3 (3), two triarylcatecholatostiboranes that differ by the nature of the aryl substituent. Fluoride anion binding studies indicate that 3 is more Lewis acidic than 2, a factor readily assigned to the steric crowding around antimony in the case of the o-tolyl derivative. But, while 3 binds F- trans to a Sb-Caryl bond as is typical of catecholatostiboranes, 2 prefers binding trans to a Sb-O bond. Computational analyses of 2 and 3 reveal the existence of several σ holes, and an activation strain analysis is employed to elucidate the origin of these stiboranes' anion-binding geometry preferences.