Organoboryl germanium(II) oxides were synthesized from the 1,4-addition reaction of L′Ge (L′ = HC[C(CH₂)N(Ar)]C(Me)N(Ar), Ar = 2,6-iPr₂C₆H₃) with selected monosubstituted arylboronic acids RB(OH)₂ (R = 2,6-Me₂C₆H₃, 2,4,6-Me₃C₆H₂, 1-Naph) at the molar ratios of 1:1 and 2:1. The mononuclear products RB(OH)OGeL (L = CH[C(Me)N(Ar)]₂, Ar = 2,6-iPr₂C₆H₃; R = 2,6-Me₂C₆H₃ (1), 2,4,6-Me₃C₆H₂ (2), 1-Naph (3)) containing the Ge–O–B core were obtained smoothly through the 1:1 reaction. However, the reaction of L′Ge with 2,6-Me₂C₆H₃B(OH)₂ in a 2:1 ratio gave only the mononuclear product (1) instead of the expected binuclear one. What’s more, a new borate compound [(2,6-Me₂C₆H₃)₄B₅O₆]^-[H:C]⁺ (4) (:C = C[N(iPr)C(Me)]₂) was concomitantly formed when the in situ prepared L′Ge was used as the precursor. In contrast, the use of 2,4,6-Me₃C₆H₂B(OH)₂ or 1-NaphB(OH)₂ as the organoboryl source in the similar reaction led to the formation and isolation of the binuclear products RB(OGeL)₂ (R = 2,4,6-Me₃C₆H₂ (5), 1-Naph (6)) containing the Ge–O–B–O–Ge core in a straight way. Compounds 1～6 were determined by single-crystal X-ray diffraction analysis.