We report here structural and photophysical studies on polyacetylene prepared by various precursor routes. We find that control of stereoregularity, molecular weight and molecular weight distribution of the precursor allows improvements in ordering parameters, such as molecular orientation and crystallographic order of the final polymer. The photophysical properties of polyacetylene also depend on the particular precursor preparation route. The peak in the pi-pi* absorption lies between 2.15 and 2.65 eV, depending on the precursor; also, photoinduced metastable band-gap states vary in position, shape and strength.