Tri and tetraazaanthracene derivatives have been considered theoretically to obtain information about their stabilities and aromaticities. The expected decrease of aromaticity of parent anthracene by tri or tetraaza substitution has been compensated by substitution of one of the hydrogens of the system by an electronegative group. The position of the substituent has been proved to be strongly effective on the aromaticity of the structure such that, the aromaticity is enhanced when the susbtituent is closer to the aza points.