Ab initio IGLO/B-11-NMR and IGLO/Cl-35-NMR calculations as well as GIAO/NMR studies on two plausible B-Cl-4-C2B4H2 structures lead to the conclusion that the only known compound of that formula most probably prefers a "classical" structure rather than a close configuration of carbon and boron atoms. IGLO and GIAO calculations on a [2.1.1] bicyclic system, perhaps fluxional in nature, with the two carbon atoms at the bridgehead positions are reasonably consistent with available NMR data. The proposed static planar structure for the known B,B’-difluoro derivative of C4B2H6 is supported by IGLO/B-11-NMR and IGLO/F-19-NMR, as well as corresponding GIAO/NMR results. Calibration of the B-11, F-19, and Cl-35 NMR correlative approaches involved the comparison of calculated and experimental NMR shifts for the simple haloboron compounds, XB(CH=CH2)(2), X(2)BCH=CH2, XBMe(2), X(2)BMe, BX(3), BX(4)(-) ion, (X=F, Cl), ClBF2, and Cl2BF.