Broad C-13 resonances, as the result of partially relaxed scalar C-13-B-11 coupling, were observed for the C-1 and to a lesser extent C-2 carbons of 1-alkynyldioxaborolanes at 25 degrees C. Measurement of the C-13 spectra at 102 degrees C resulted in a slower B-11 quadrupolar relaxation rate and allowed the determination of (1)J(C-13,B-11) sealer coupling from the resulting quadruplets for the C-1 carbon.