Base precursor for heat-developable photosensitive material

A base precursor for heat-developable photosensitive material, represented by the general formula (I) or (II):

• (R--C.tbd.C--CO.sub.2 H).sub.x.B (I)
• R--C.tbd.C--CO.sub.2 H).sub.2.B.sub.y (II)
• wherein, R represents a monovalent group selected from the group consisting of a hydrogen atom, an alkyl group, a substituted alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted aryl group, a heterocyclic group, a substituted heterocyclic group, an aralkyl group, a substituted aralkyl group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, a substituted carbamoyl group, --CO.sub.2 M (M is an alkali metal) and --CO.sub.2 H.B, or a divalent group selected from the group consisting of a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group and a substituted or unsubstituted heterocyclic divalent group;
• B represents an organic base;
• x represents 1 when B is a monoacidic base, and 2 when B is a diacidic base;
• and
• y represents 2 when B is a monoacidic base, and 1 when B is a diacidic base.