Abstract: A leuco dye having the formula ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represent a lower alkyl group; R.sup.5 represents an .alpha.-naphthyl group, .beta.-naphthyl group or ##STR2## wherein R.sup.6 represents --NHCOR.sup.9, a halogen or an amino group which is unsubstituted or substituted by one or two C.sub.1 -C.sub.4 alkyl groups which are the same or different; and R.sup.7, R.sup.8 and R.sup.9 each represent hydrogen or a lower alkyl group, provided that when both R.sup.7 and R.sup.8 are hydrogen, R.sup.6 represents --NHCOR.sup.9 or bromine.These dyes absorb in the near-infrared region and yield colored images with a color developer therefor with excellent preservability.

Abstract: A recording material employing at least one leuco dye having formula (I), which is colored when brought into contact with a color developer capable of inducing color formation in the leuco dye: ##STR1## wherein R.sup.1 and R.sup.2 each represent an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group, an unsubstituted or substituted aralkyl group, or an unsubstituted or substituted aryl group, which R.sup.1 and R.sup.2 may form a ring in combination or a morpholine ring through an oxygen atom; R.sup.3 represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms or an aralkyloxy group; R.sup.4 and R.sup.5 each represent an alkyl group having 1 to 4 carbon atoms; and R.sup.6 represents hydrogen, an alkyl group having 1 to 4 carbon atoms or a halogen.

Abstract: A leuco dye having the formula ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represent a lower alkyl group; R.sup.5 represents an .alpha.-naphthyl group, .beta.-naphthyl group or ##STR2## wherein R.sup.6 represents --NHCOR.sup.9, a halogen or an amino group which is unsubstituted or substituted by one or two C.sub.1 -C.sub.4 alkyl groups which are the same or different; and R.sup.7, R.sup.8 and R.sup.9 each represent hydrogen or a lower alkyl group, provided that when both R.sup.7 and R.sup.8 are hydrogen, R.sup.6 represents --NHCOR.sup.9 or bromine.These dyes absorb in the near-infrared region and yield colored images with a color developer therefor with excellent preservability.

Abstract: A dichroic dye for use in a liquid crystal comprising at least one compound represented by a formula: ##STR1## The compound includes monoazo, disazo and trisazo compounds. The dye has a high dichroic ratio, a high mole absorptivity and a good compatibility with liquid crystals.