Abstract: The present invention relates to a carbodiimide derivative represented by the following general formula:W.sub.1 --X--N.dbd.C.dbd.N--Y--W.sub.2 --Zwherein W.sub.1 is a straight chain, branched chain or cyclic saturated or unsaturated aliphatic hydrocarbon group, a substituted or unsubstituted aryl group, a heteroaryl group, a tertiary amino group or a tertiary or quaternary ammonium group; --W.sub.2 --Z is a quaternary ammonium group; X and Y are each independently a single bond or an alkylene group; and Z is a biotin group represented by the following formula: ##STR1## wherein n is 0 or 1. The derivative is useful as a label reagent for introducing a biotin group into a nucleic acid or a protein.

Abstract: The present invention relates to a carbodiimide derivative represented by the following general formula:W.sub.1 --X--N.dbd.C.dbd.N--Y--W.sub.2 --Zwherein W.sub.1 is a straight chain, branched chain or cyclic saturated or unsaturated aliphatic hydrocarbon group, a substituted or unsubstituted aryl group, a heteroaryl group, tertiary amino group or a tertiary or quaternary ammonium group; --W.sub.2 --Z is a quaternary ammonium group; X and Y are each independently a single bond or an alkylene group; and Z is a biotin group represented by the following formula: ##STR1## wherein n is 0 or 1. The derivative is useful as a label reagent for introducing a biotin group into a nucleic acid or a protein.

Abstract: An aromatic diamine compound represented by formula (1): ##STR1## wherein R.sub.1 and R.sub.2, which may be the same or different, are each a hydrogen atom or a lower alkyl group; and an aromatic diamine compound useful as an intermediate for the synthesis of the above compound (1), represented by formula (2): ##STR2## The compound (1) alleviates the problems of the prior art, and is unlikely to cause crystallization by heat and has a melting point and a glass transition temperature both higher than those of conventional compounds.