2-Ethylhexanoyl chloride was used in the preparation of 4-aza-6-ethyl-4-(2-ethylhexanoyloxy)-5-oxodecyl 2,3, 4,6-tetra-O-acetyl-l-thio-β-D glucopyranoside. It was also used in the preparation of poly(4,8-bis-alkyloxybenzo(1,2-b:4,5-b′)dithiophene-2,6-diyl-alt-(alkyl thieno(3,4-b)thiophene-2-carboxylate)-2,6-diyl), having very promising photovoltaic properties. 2-Ethylhexanoyl chloride was used in the preparation of 4-aza-6-ethyl-4-(2-ethylhexanoyloxy)-5-oxodecyl 2,3, 4,6-tetra-O-acetyl-l-thio-β-D glucopyranoside. It was also used in the preparation of poly(4,8-bis-alkyloxybenzo(1,2-b:4,5-b′)dithiophene-2,6-diyl-alt-(alkyl thieno(3,4-b)thiophene-2-carboxylate)-2,6-diyl), having very promising photovoltaic properties.