Boron co-ordination compounds of the type L.BH, (L = Me,N. Et,N. Py. and Et,P) and Me,N,BH,X (X = CI, Br, and I) areshown to form hydrogen-bonded complexes with OH (MeOH. PhOH. and p-F*C6H,*OH) in carbon tetrachloride solution. These complexes appear to be formed via OH . . . BH, and OH . . . BH, interactions and are readily detected by the appearance of a low-frequency i.r. OH stretch. Formation of similar complexes with the more extensively halogenated amine-boranes Me,N,BHX, (X = CI. Br, and I) and Me,N,BX, (X = F, CI, and Br) could not be observed. Cyclotriborazanes (RNH-BH,), are shown to undergo self-association in solution and this is attributed to a related NH . . * BH, interaction.WE have reported the appearance of low-frequency O-H stretching absorptions upon addition of Me,N ,BH, to dilute solutions of methanol and phenol in carbon tetrachloride. We suggested that these absorptions are due to the formation of hydrogen-bonded complexes in which the BH, group acts as a proton acceptor. In this paper we examine the interaction of hydroxylic compounds (MeOH, PhOH, and fi-F*C,H,*OH) with