5′-Alkoxy-2,2′-bithiophene azo dyes: a novel promising series of NLO-chromophores

New efficient and thermally stable NLO-chromophores 3-5 based on a 5-alkoxy-2,2′-bithiophene donor π-conjugated bridge and a phenylazo acceptor moieties were synthesized by diazo coupling reactions of 5-alkoxy-2,2′-bithiophenes 1 with substituted aryldiazonium salts 2.