4-Thiazolidinone, 5,5'-[[4,8-bis[(2-ethylhexyl)thio]benzo[1,2-b:4,5- b']dithiophene-2,6-diyl]bis[(3,3''-dioctyl[2,2':5',2''-terthiophene]-5'',5-diyl)methylidyne]]bis[3-ethyl-2-thioxo-