Azo dye, ink jet recording ink, heat sensitive recording material, color toner, color filter, ink jet recording method, ink cartridge and ink jet printer

An azo dye represented by formula (I):

• wherein A represents a residue of a 5-membered heterocyclic diazo component A-NH2;
• B1 and B2 each represents ═CR1— or ═CR2—, or one of B1 and B2 represents a nitrogen atom and the other of B1 and B2 represents ═CR1— or ═CR2—;
• R3 and R4 each independently represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group or a sulfamoyl group, each of the groups optionally has a substituent;
• R1 and R2 each independently represents a hydrogen atom, a halogen atom, an aliphatic group, an aromatic group, a heterocyclic group, a cyano group, a carboxyl group, a carbamoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyl group, a hydroxyl group, an alkoxy group, an aryloxy group, a silyloxy group, an acyloxy group, a carbamoyloxy group, a heterocyclic oxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, an alkylamino group, an arylamino group, a heterocyclic amino group, an acylamino group, an ureido group, a sulfamoylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, an alkylsulfonylamino group, an aryloxycarbonylamino group, a nitro group, an alkylthio group, an arylthio group, an alkylsulfonyl group, an arylsulfonyl group, an alkylsulfinyl group, an arylsulfinyl group, a sulfamoyl group, a sulfo group or a heterocyclic thio group, each of the groups optionally has a substituent, and R1 and R3 are optionally taken together, or R3 and R4 are optionally taken together, each to form a 5- or 6-membered ring;
• a and e each independently represents an alkyl group, and the alkyl groups represented by a and e have at least three carbon atoms in total that constitute the alkyl groups, and each of the groups optionally has a substituent;
• b, c, and d each independently has a same meaning as R1 and R2, and a and b are optionally taken together, or e and d are optionally taken together, each to form a condensed ring;
• and
• formula (I) has at least one ionic hydrophilic group.