In the title spiro compound, C(29)H(24)N(4)S, the quinoxaline and thia-diazole ring systems share a common C atom; their mean planes are aligned at 87.0 (1)° in one mol-ecule and at 84.1 (1)° in the other independent mol-ecule. The thia-zole ring possesses two aromatic ring substituents and is roughly coplanar with these rings [the dihedral angles between the thia-diazole and phenyl rings are 10.7 (1) and 11.7 (1)° in one mol-ecule, and 16.8 (1) and 17.7 (1)° in the other]. The aromatic ring of the benzyl unit of one mol-ecule is disordered over two orientations in a 1:1 ratio.