Diethyl 3-amino-4-[(triphenylphosphoranylidene)amino]thieno[2,3-b]thiophene-2,5-dicarboxylate

The asymmetric unit of the title compound, C30H27N2O4PS2, consists of two crystallographically independent molecules. The thieno[2,3-b]thiophene ring systems are planar. One of the terminal ethyl groups is disordered over two positions; the site occupancy factors are ca 0.7 and 0.3. The crystal structure is stabilized by N—H⋯N, N—H⋯O and C—H⋯O hydrogen bonds.