Phenylnaphthol derivatives represented by the following general formula (1), wherein, R1 to R3 are hydrogen atoms, alkyl groups or aryl groups, and R2 and R3 may be bonded together to form an aliphatic hydrocarbon ring or a heterocyclic ring, a and b are, respectively, integers of 0 to 4, R4 and R5 are hydroxyl groups, alkyl groups, haloalkyl groups, cycloalkyl groups, alkoxy groups, amino groups, heterocyclic groups having a nitrogen atom as a hetero atom and are bonded together via the nitrogen atom, cyano groups, nitro groups, formyl groups, hydroxycarbonyl groups, alkylcarbonyl groups, alkoxycarbonyl groups, halogen atoms, aralkyl groups, aralkoxy groups, aryloxy groups, aryl groups, heteroaryl groups bonded together via a carbon atom in the ring, alkylthio groups, cycloalkylthio groups, arylthio groups or heteroarylthio groups, and if R4 or R5 are present in a plural number, the plurality of R4 or the plurality of R5 may be the same or different, or 2 R4s or 2 R5s may be bonded together to form an alicyclic hydrocarbon ring or a heterocyclic ring. The compounds are useful as intermediate products for the synthesis of, for example, photochromic compounds.