An enhancement of through-bond interaction by bond angle distortion in pyrazine was examined using various MO methods. Results of MINDO/3 geometry optimization with an angle (${alpha}$) at $C_2$ atom fixed to 120∼90$^{circ}$ lead to distorted structures in which the distorted bond is brought closer toward lone pair orbital n of N atom. It was also found that the bond angle distortion increased the P character at the atom $C_2$, resulting in an increased vicinal overlap between n and the $C_2-C_3$ bond. The FMO patterns of ${sigma}$ framework showed three-fold degeneracy, one of which was of different symmetry which mixes in the symmetry adapted pair, $n_+;and;n_-;;both;n_+;and;n_-$ orbitals thus can interact with both FMOs of the ${sigma}$ framework. The LCBO-MO analysis with partial elimination of bonds, antibonds or both, however, revealed that the main interaction of $n_+$ was with the HO-${sigma}$ and that of $n_-$ was with the LU-${sigma}^{ast}$ orbital of the ${sigma}$ framework.