The molecule is an organosulfonate oxoanion obtained by deprotonation of the sulfo group of 2'-(4-aminophenyl)-6-methyl[2,6'-bi-1,3-benzothiazole]-7-sulfonic acid. It is a conjugate base of a primuline (acid form).
2-[2-(4-aminophenyl)-1,3-benzothiazol-6-yl]-6-methyl-1,3-benzothiazole-7-sulfonate