The twisted aromatics,functional dibenzo[d,f][1,3]dioxepine derivatives were synthesized in high yields from reactions of 5,5'-dibromo-2,2'-biphenol with corresponding ketal or ketone compounds under acid catalysis.The structures of these compounds were characterized by 'H NMR,elemental analysis,UV-Vis absorption spectrum and X-ray diffraction analysis.The conformation of O-C-O bridged biphenyl derivatives with varied substitute groups on 6,6'-position was studied by X-ray crystallography and force-field simulation.The result of calculations by UNIVERSAL 1.02 force field in Cerius2 package(4.6) indicates that dibenzo[d,f][I,3]dioxepine derivatives show twisted conformations and the twisted angle between the phenyl rings is about 40℃,which is accordant with the result from crystal structure determination,though the obtained angles in the crystal of dibenzo[d,f][1,3]dioxepine derivatives with the varied substitute groups on 6,6'-position are shown to be slightly shifted to 40℃ owing to intermoleeular interactions in crystal stacking.DSC studies exhibit that the substitute groups on 6,6'-position can induce a large variation of endothermie peaks ranging from 80 to 135℃.The conjugated polymers based on dibenzo[d,f][l,3]dioxepine derivatives,which have ultraviolet emitting with a quantum efficiency of 10%,were obtained by Yamamoto coupling.