Dimethyltinselenid reacts with diorganyliodoboranes to give R2B—Se—BR2. The compounds with R = C6H11 and C6H5 are stable, whereas with R = CH3 and C4H9 decomposition to polymeric (RBSe)n was observed. Diboryldiselenanes have been obtained from (C5H5)2TiSe5 and R2B—I as well as from borolane and elemental selenium. At higher temperature these diboryldiselenanes decompose to form triselenadiborolanes and trialkylboranes.