A color-developing sheet for pressure-sensitive recording sheets, said sheet comprising as a color-developing agent at least one 2,2'-bisphenolsulfone zinc salt selected from compounds of the general formula ##STR1## wherein R.sub.1 and R.sub.2 are identical or different, and represent a hydrogen atom, a halogen atom, an alkyl group containing 1 to 10 carbon atoms, a cycloalkyl group containing 3 to 10 carbon atoms, an aralkyl group containing 7 to 11 carbon atoms, or a phenyl group.