A heat developable photosensitive material comprising a support having thereon at least one light-sensitive layer comprising light-sensitive silver halide and a binder, wherein at least one layer contains a base precursor represented by the following general formula (I): ##STR1## wherein at least one of X, Y and Z, which may be the same or different, represents an electron-attractive substituent selected from the group (a) consisting of a halogen atom, a nitro group, an alkysulfinyl group, an arylsulfinyl group, an acyl group, a sulfamoyl group, a sulfamoyl group substituted with an aryl group, a substituted aryl group, an alkyl group or a substituted alkyl group, a carbamoyl group, a substituted carbamoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an aryloxysulfonyl groups ##STR2## a nitroso group, ##STR3## wherein B is defined as in general formula (I), and R, R.sup.1 and R.sup.2 each represents a hydrogen atom, an alkyl group or an aryl group, and the alkyl or aryl moiety of these groups may be further substituted;the remainder of X, Y and Z being selected from the group (b) consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, a silyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group and a hydroxy group, wherein the alkyl and aryl moieties may be further substituted with a substituent other than a perhaloalkyl group containing up to 3 carbon atoms,provided that at least one of X, Y and Z represents a group other than a halogen or a nitro group, and any two of X, Y and Z may combine to form a ring;B represents a mono-acidic or di-acidic base having a pKa value of at least 7 and containing not more than 12 carbon atoms; andn and m each represents 1 or 2, provided that the net charge of the compound is zero.