All planar homopairings of the artificial nucleobase 1H-benzoimidazole-4,7-dione are reported for the first time in this study. Using the idea of binding sites discussed in our previous work and an ab initio density functional theory method we predict 13 homopairs. The stabilization energies of the homopairs vary from -0.13 to -0.69 eV. The collected data on all the planar homopairs reported here may be useful when constructing assemblies of this artificial base on various solid substrates.