Labelled complex

A method of detecting a subject compound to be analyzed by means of optical means which method comprises using a labeled complex comprised of a substance from a living organism and a labeling agent fixed onto the substance and bonding the complex to the subject compound to be analyzed, wherein the labeling agent comprises a compound represented by the general formula (I), (II) or (III):

• ##STR99## wherein R.sub.1 through R.sub.7 are independently selected from the group consisting of hydrogen, halogen, alkyl, aryl, aralkyl, sulfonate, amino, styryl, nitro, hydroxyl, carboxyl, cyano, and arylazo;
• R.sub.1 through R.sub.7 may be bonded to each other to form a substituted or an unsubstituted condensed ring;
• F.sub.1 represents a divalent organic residue;
• and
• X.sub.1.sup..crclbar. represents an anion;
• ##STR100## wherein R.sub.8 through R.sub.14 are independently selected from the group consisting of hydrogen, halogen, alkyl, aryl, aralkyl, sulfonate, amino, styryl, nitro, hydroxyl, carboxyl, cyano, and arylazo;
• R.sub.8 through R.sub.14 may be bonded to each other to form a substituted or an unsubstituted condensed ring;
• and
• F.sub.2 represents an anionic divalent organic residue ##STR101## wherein R.sub.15 through R.sub.21 are independently selected from the group consisting of hydrogen, halogen, alkyl, aryl, a substituted or an unsubstituted aralkyl, a substituted or an unsubstituted amino, a substituted or an unsubstituted styryl, nitro, sulfonate, hydroxyl, carboxyl, cyano, and arylazo;
• R.sub.15 through R.sub.21 may or may not be bonded to each other to form a substituted or an unsubstituted condensed ring;
• F.sub.3 represents a cationic divalent organic residue;
• and
• X.sub.1.sup..crclbar. represents an anion.