A convenient method for the preparation of strongly Lewis acidic tris-perfluoro-tert-butoxyborane B(ORF)3 (1), (ORF = OC(CF3)(3)) was developed, and its X-ray structure was determined. 1 was used as a precursor, guided by density functional theory (DFT) calculations and volume-based thermodynamics, for the synthesis of [NEt4][NCB(ORF)(3)] (3) and [NMe4][FB(ORF)(3)] (5) and the novel large and weakly coordinating anion salts [Li 15-Crown-5][B(ORF)(4)] (2) and [NEt4][CN{B(ORF)(3)}(2)] (4). The stability of [B(ORF)(4)](-) was compared with that of some related known weakly coordinating anions by appropriate DFT calculations.