Characteristic properties of order parameters and layer structures of highly oriented poly [(m-hydroxyphenyl)butylsilane] (PPBS), poly[[(m-potassiooxy)phenyl]butylsilane] (PPBS-K), and poly[(6-hydroxyhexyl)hexylsilane] (PHHS) were studied by polarized fluorescence measurement and small-angle X-ray diffraction. Samples were prepared by the Langmuir-Blodgett (LB) technique. The temperature dependence of the order parameter ((P) over bar(2), (P) over bar(4)) in PPBS and PHHS can be determined by the fluorescence depolarization ratios (r(1) and r(2)). The order-disorder conformational transitions of PPBS and PHHS occur at T-c = 130.0 and 100.0 degrees C, respectively. (P) over bar(2)’s and (P) over bar(4)’s) of PPBS are higher than those of PHHS. (P) over bar(2)’s of PPBS and PHHS depend clearly on the temperature, while the (P) over bar(4)’s show steady negative values which increase slightly near T-c. X-ray diffraction patterns taken at room temperature show that the steroregularities of PPBS, PPBS-K, and PHHS thin films are completely different. PPBS shows a long and a short period peak. This long period peak is observed for the first time in oriented thin films for poly(silane)s. That is, the oriented PPBS film is constituted as a bilayer structure with one hydrogen bond and one hydrophobic bond in view of facts that the temperature dependence of intensity, peak shift, and full width at half maximum in two X-ray diffraction peaks are clearly different. One layer spacing and amorphous states are found in PPBS-K, and PHHS does not have a regular layer but indicates a broad amorphous feature. The amorphous states of PPBS-K and PHHS are considered to be of different origin because the amorphous X-ray diffraction feature of PPBS-K differs clearly from that of PHHS. The sharp peak of PPBS-K cannot originate from the same layer spacing of PPBS since hydrogen bonding is stereochemically hindered by the potassium atoms of PPBS-K. The disappearance of two layer spacings in PPBS is in accordance with the Lindeman’s criterion of melting, when the temperature approaches T+. similar to 1.0 where T+ means a reduced temperature. It can be also found that deviations of the second-order parameters around their equilibrium values in PPBS and PHHS approach similar to 1/5, as the temperature is raised near T* = 1.0 where T*(= T/T-c) is a reduced temperature.