A liquid crystal device is formed by applying an alignment film comprising a polyimide which contains a structural unit represented by the following formula (I): ##STR1## wherein R.sub.1 denotes a tetravalent organic residue group, R.sub.2 denotes a divalent organic residue group, X denotes --NHR.sub.3 or --OH, R.sub.3 denotes an alkyl group having 5-20 carbon atoms, Y denotes --NHR.sub.4 or --OH, and R.sub.4 denotes an alkyl group having 5-20 carbon atoms with the proviso that both X and Y cannot be --OH and the --OH in X or Y can be removed by further cyclization. The liquid crystal device thus formed shows a high contrast display, particularly by multiplexing drive, free from after-image because of quick responsiveness.