NEW MATERIAL:A diazo compound obtained by reaction of phenols having alkyl in which α-position or β-position is substituted with hydroxy, holgen, acyloxy, alxoycarbonyl or oxirane ring at m-position with a diazonium salt.

EXAMPLE: An o-phenylazo-m-hydroxyphenyl dimethyl carbinol.

USE: Useful as drugs, agricultural chemicals, dye, various intermediates and indole precursor, etc.

PREPARATION: A diazonium salt is reacted with phenols having alkyl group substituted with a double bond precursor group (especially α-opposition or β-position is substituted with OH, halogen, carbonyl, acyloxy, tosyloxy, triple bond, cyclopropane or oxirane ring) at m-position to afford the aimed diazo compound.