Synthesis and photochromic properties of thiophene linked [2H]-chromenes

Successive coupling reactions (catalysed by Cu(I)/Pd(II) systems) between 8 -bromo-3,3-diphenyl-[3H]naphtho[2,1-b]pyran, 2-methylbut-3-yn-2-ol and appr opriate thiophene- or bithiophene halides afforded mono- or bichromophoric chromenes bearing a thienylethynyl or a bithienyrethynyl group. Spectrokine tic study using flash photolysis conditions showed interesting photochromic properties regarding, especially, the " colorability " of the new compound s.