Heat-sensitive recording material

In a heat sensitve recording material composed of a colorless or pale dye, a color developer and a sensitizer, the improvement comprising including benzoin derivatives represented by formula (I) as the sensitizer to obtain improved color forming sensitivity and preservability of the said heat sensitive recording material:

• ##STR5## wherein p is an integer of 0 or 1,
• X.sub.1 and X.sub.2 are selected from the group consisting of hydrogen, halogens, nitro, acyl, aryl, aryloxy, linear, branched C.sub.1 -C.sub.10 alkyl and C.sub.1 -C.sub.10 alkyloxy,
• Y.sub.1 and Y.sub.2 are selected from the group consisting of hydrogen, halogens, nitro, acyl, aryl, aryloxy, linear C.sub.1 -C.sub.10 alkyloxy, and branched C.sub.1 -C.sub.10 alkyloxy,
• R.sub.1 is selected from the group consisting of hydrogen, cyano, hydroxy, aralkyloxy, alkyloxy, aryloxy and --OR wherein R represents C.sub.1 -C.sub.10 alkyl, C.sub.1 -C.sub.10 acyl, C.sub.1 -C.sub.10 alkoxycarbonyl, aryloxy carbonyl,
• R.sub.2 is selected from the group consisting of hydrogen, linear C.sub.1 -C.sub.10 alkyl, branched C.sub.1 -C.sub.10 alkyl, C.sub.1 -C.sub.10 alkenyl, C.sub.1 -C.sub.10 hydroxyalkyl, cyclohexyl, aryl and ##STR6## wherein n is an integer of 1,2, or 3, and Z is selected from the group consisting of hydrogen, halogens, lower alkyl, nitro, alkoxy, and acyl.