The electronic structures of simplified poly(disilanylene(thienylene)(
n)) (n = 1-5) have been studied in detail on the basis of the one-dime
nsional tight-binding self-consistent field-crystal orbital method. Th
e result suggests that the sp(3)-hybridized orbital of silicon atoms a
lmost cuts off the pi-conjugation occurring from the thienylene units.
The pi-pi interband transition energy becomes smaller with an increa
se of n (number of thiophene rings), while the sigma-sigma one shows
almost no change. Electronic structures of poly(ethylene(thienylene)(n
)) (n = 1-3), poly(silylene(thienylene)(n)) (n = 1), and polythiophene
have also been examined for comparison.