An IR-absorbing naphthalocyanine dye of formula (I) is described: wherein M is Ga(A1); A1 is an axial ligand selected from —OH halogen, —OR3, —OC(O)R4; R1 and R2 may be the same or different and are selected from hydrogen or C1-12 alkoxy; R3 is selected from C1-12 alkyl, C5-12 aryl, C5-12 arylalkyl or Si(Rx)(Ry)(Rz); and R4 is selected from C1-12 alkyl, C5-12 aryl or C5-12 arylalkyl Rx, Ry and Rz may be the same or different and are selected from C1-12 alkyl, C5-12 aryl, C5-12 arylalkyl, C1-12 alkoxy, C5-12 aryloxy or C5-12 arylalkoxy; and W is a sulfonic acid group, including salts thereof.