Bazzi and Mitter showed that binary dihedral group codes are asymptotically good. In this paper we prove the over any finite field with strong duality property If characteristic of is even, self-dual odd, maximal self-orthogonal LCD

Let ? be a simple undirected graph on finite vertex set and let A its adjacency matrix. Then is singular if singular. The problem of characterizing graphs easy to state but very difficult resolve in any generality. In this paper we investigate the singularity for which dihedral group acts transitively vertices as automorphisms.