B,N-GRs are a broad class of chromophores with spectroscopic and photophysical properties which can be systematically optimized for optoelectronic applications. The S1 excitation energies of short ribbons considered herein cover a range from about 0.8 eV to about 1.8 eV. The higher density of heteroatoms in the CBN_2 and CBN_4 ribbons results in S1 excitation energies which are higher than those of the CBN_1 and CBN_3 ribbons with lower density of heteroatoms, albeit the excitation energies of all ribbons converge to about 1.2 eV for large ribbons. The CBN_1-m and CBN_3-m ribbons exhibit robust inversion of the S1 and T1 excitation energies for small m. The S1 and T1 excitation energies of the CBN_2-m and CBN_4-m ribbons, on the contrary, are nearly degenerate for all m. For all four types of ribbons, the singlet-triplet gap tends towards zero for large m.