The reduction of substituted isoflavones with sodium borohydride catalyzed by cobalt(II) phthalocyanines has been achieved efficiently to yield cis- and trans-isoflavan-4-ols under mild conditions via the formation of a hydridocobalt(III) phthalocyanine intermediate. The hydroxy isoflavones react with sodium borohydride to form the corresponding phenolate moiety and thereby prevent the formation of a hydridocobalt(III) phthalocyanine intermediate which inhibits its reduction to corresponding isoflavan-4-ols.