| abstract |
Chromogenic compounds of normally colorless form are disclosed having the following structural formula: wherein E represents a six-membered aromatic or heterocyclic ring which may have an aromatic condensed ring and both the E ring and the condensed ring may be substituted, A represents an optionally substituted aminophenyl, indolyl, benzoindolyl, julolidinyl or kairolyl radical or the radical represented by B, and B represents a family of heterocyclic radicals. The compounds of this invention are eligible for use in pressure-sensitive and heat sensitive record materials and manifold marking systems. |