Dyestuffs of the oxidizable developer-coupler type wherein the developer is a novel 4,7-diaminoindazole of the formula: ##STR1## wherein one of the R's represents C.sub.1-4 alkyl and the other R represents a substitutent selected from the group consisting of C.sub.1-4 alkyl and H (and the water-soluble salts thereof) are very satisfactory for coloring hair. They are readily oxidized by atmospheric oxygen at room temperature without a catalyst, and they provide intense, bright, and fast dyeings in a short time. They are applied in conventional manner from aqueous medium.