The present invention provides an IR-absorbing naphthalocyanine dye of
formula (I): ##STR00001## wherein M is selected from Ga(A.sup.1);
A.sup.1 is an axial ligand selected from --OH, halogen (preferably Cl),
--OR.sup.3, a hydrophilic ligand and/or a ligand suitable for reducing
cofacial interactions; R.sup.1 and R.sup.2 may be the same or different
and are selected from hydrogen or C.sub.1-12 alkoxy (preferably C.sub.1-6
alkoxy); R.sup.3 is selected from C.sub.1-12 alkyl, C.sub.5-12 aryl,
C.sub.5-12 arylalkyl or Si(R.sup.x)(R.sup.y)(R.sup.z); and R.sup.x,
R.sup.y and R.sup.z may be the same or different and are selected from
C.sub.1-12 alkyl, C.sub.5-12 aryl, C.sub.5-12 arylalkyl, C.sub.1-12
alkoxy, C.sub.5-12 aryloxy or C.sub.5-12 arylalkoxy; W is a hydrophilic
group; n1 is 0, 1, 2 or 3; n2 is 0, 1, 2 or 3; n3 is 0, 1, 2 or 3; n4 is
0, 1, 2 or 3; provided that at least one of n1, n2, n3 or n4 is greater
than 0.Dyes of this type are especially suitable for use in netpage and
Hyperlabel.TM. systems.
