Abstract: The fluoran compounds of the formula (I) are new red color forming chromogenic dyes. ##STR1## wherein R represents an isobutyl or isopentyl group, R.sub.1 represents a hydrogen or halogen atom or an alkyl group, R.sub.2 represents a hydrogen or halogen atom or an alkyl group, R.sub.3 represents a hydrogen atom, and R.sub.4 represents a hydrogen atom, or R.sub.4 and R.sub.1 as well as R.sub.2 and R.sub.3 taken together with the carbon atoms to which they are attached may form a benzene ring which may be substituted with a halogen atom. They are used, together with an acidic developer, in chromogenic recording materials for use in pressure sensitive copying paper, heat-sensitive recording paper and thermo-sensitive, reversible color changing composition.

Abstract: A thermally-sensitive color-forming composition is disclosed which comprises chromogenic material and certain acidic developer material. Record material comprising this color-forming composition exhibits greatly improved background coloration.