Red Colouring Hyperchromic 3H-Naphtho[2,1-b]pyrans

Red colouring hyperchromic compounds having general formula (I), where R?1¿ is H, NR?2¿R?3¿, OR?4¿, SR?4¿ or R?7¿ wherein R?2¿ and R?3¿ are alkyl or carbocyclic groups or together with the nitrogen to which they are attached form a heterocyclic ring; R?4¿ is the same as R?1¿ or is alkyl, perhaloallyl, aryl or heteroaryl; R?7¿ is alkyl, haloalkyl, alkylthio, aryl, arylthio, heteroaryl, halogen, nitrile, carboxylate, ester, nitro, or a carbocyclic or heterocyclic ring fused to faces f, gh, i, j or k; and R?5¿ is a cyclic aminoaryl group, an indolinoaryl group, a tricyclic nitrogen heterocycle, or an unsaturated cyclic aminoaryl group.