Propanedinitrile, 2,2'-[[4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl]bis[[4-[(2-ethylhexyl)oxy]-5,2-thiophenediyl]-(Z)-methylidyne(3-oxo-1H-indene-2,1(3H)-diylidene)]]bis-;