Bis(catecholato)diboron was added to cyclic alkenes with internal strain to selectively form bis(boryl)cycloalkanes quantitatively in the presence of [Pd(NHC)pyCl₂], [Pd(NHC)pyI₂], and [Pt(NHC)pyI₂] (NHC=N-heterocyclic carbene, py=pyridyl), which have been synthesized and characterized for the first time in this study.