Abstract: Novel phenolic compounds useful as a color developer suitable for satisfying the quality requirements of heat-sensitive recording materials are provided, which compounds are expressed by the general formula ##STR1## wherein R.sub.1 represents an alkyl group or a cycloalkyl group and R.sub.2 represents hydrogen atom or an alkyl group; and also heat-sensitive recording materials usable in a broad application field are provided, which recording materials are provided with a heat-sensitive recording layer composed mainly of a colorless basic dye and the above compounds as a color developer by which the dye forms colors, overlaid on a substrate.

Abstract: In a heat-sensitive recording material incorporating a colorless or pale-colored basic dye and a color acceptor which is reactive with the basic dye to form a color when contacted therewith, the recording material characterized in that at least one compound represented by the formula [I] is contained in a heat-sensitive recording layer ##STR1## wherein X is --O-- or --COO--, R.sub.1 to R.sub.4 are each hydrogen atom, alkyl having 1 to 8 carbon atoms, aryl having 6 to 10 carbon atoms, aralkyl having 7 to 9 carbon atoms, chlorine atom, acetyl, propionyl, methoxy, methylthio, methoxycarbonyl, cyano, nitro or cyclohexenyl, substituents R.sub.1 and/or R.sub.2 or substituents R.sub.3 and R.sub.4 may link together to form aromatic ring(s), n is an integer of 1 to 10.

Abstract: In a heat-sensitive recording material incorporating a colorless or pale-colored basic dye and a color acceptor which is reactive with the dye to form a color when contacted therewith, the recording material characterized in that the color acceptor comprises at least one compound represented by the formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each a hydrogen atom, alkyl having 1 to 8 carbon atoms, aryl or aralkyl, provided that R.sub.1 and R.sub.2, as well as R.sub.3 and R.sub.4, are not hydrogen at the same time.