We have theoretically analyzed the geometrical H/D isotope effect of HNO center dot center dot center dot XH2NH2 (X = B or Al) and HNO center dot center dot center dot BH3NH3 systems with the aid of multicomponent quantum mechanics (MC_QM) method, which can directly include the nuclear quantum effect of hydrogen nuclei. We demonstrate that deuterium substitution of positively charged hydrogen in blue-shifting dihydrogen-bonded clusters leads to elongation of the dihydrogen-bonded distance, whereas the substitution of negatively charged hydrogen leads to contraction, as is the case in red-shifting dihydrogen-bonded clusters.