Patent ID: 8778236

Claim:
A chromene compound having a central skeleton represented by the following formula (1): wherein either one or both of X and Y are sulfur atoms, and when one of them is a sulfur atom, the other is an oxygen atom or group represented by the following formula, R 12 is a hydrogen atom, hydroxyl group, alkyl group, haloalkyl group, cycloalkyl group, alkoxy group, halogen atom, aralkyl group, aralkoxy group, aryloxy group or aryl group, R 1 and R 2 are each independently a hydrogen atom, hydroxyl group, alkyl group, haloalkyl group, cycloalkyl group, alkoxy group, amino group, heterocyclic group having a ring member nitrogen atom and bonded to a carbon atom bonded thereto via the nitrogen atom, cyano group, nitro group, formyl group, hydroxycarbonyl group, alkylcarbonyl group, alkoxycarbonyl group, halogen atom, aralkyl group, aralkoxy group, aryloxy group or aryl group, R 1 and R 2 may form an aliphatic ring having 3 to 20 ring member carbon atoms together with a carbon atom bonded thereto, and “a” is an integer of 1 to 3.