Diazomerocyanines and mesomeric forms thereof

A diazamerocyanine, including the mesomeric forms thereof, having the formula

• A.dbd.N--N.dbd.B"
• wherein A is of the formula ##STR92##
• wherein:
• R is selected from the group consisting of lower alkyl having 1-4 carbon atoms and phenyl;
• X is selected from the group consisting of oxygen;
• sulfur;
• --NR'--, wherein R' is lower alkyl having 1-4 carbon atoms;
• --CR'.sub.9 .dbd.CR'.sub.10 wherein R'.sub.9 is hydrogen, alkyl of 1 to 4 carbon atoms or cyano and wherein R'.sub.10 is hydrogen or alkyl of 1 to 4 carbon atoms;
• ##STR93## wherein R" is selected from the group consisting of hydrogen and lower alkyl having 1-4 carbon atoms;
• and --C(R")(R")--, wherein R" each independently have the meaning given above;
• R.sub.7 is selected from the group consisting of hydrogen, lower alkyl having 1-4 carbon atoms, cyano and phenyl;
• R.sub.8 is selected from the group consisting of hydrogen, halogen and lower alkyl having 1-4 carbon atoms, provided that R.sub.7 and R.sub.8, when taken together with the carbon atoms to which they are linked, form a benzene ring or a benzene ring substituted by halo, a lower alkyl having 1-4 carbon atoms, lower alkoxy having 1-4 carbon atoms or nitro;
• and B" is ##STR94## wherein:
• Y represents a member selected from the group consisting of ##STR95## wherein R.sub.11, and R.sub.12, each independently represent a member selected from the group consisting of hydrogen and lower alkyl having 1-4 carbon atoms, and z.sup.- halide, perchlorate, fluoroborate, acetate, bisulfate or sulfate;
• R.sub.25 represents a member selected from the group consisting of hydrogen and ##STR96## wherein W represents a member selected from the group consisting of oxygen and sulfur, and R' represents a member selected from the group consisting of amino and lower alkyl having 1-4 carbon atoms;
• and R.sub.26 and R.sub.27 each independently represent a member selected from the group consisting of hydrogen, lower alkyl having 1-4 carbon atoms and methoxy;
• provided that R.sub.27 represents hydrogen when R.sub.11, and R'.sub.12 and R.sub.25 represent hydrogen.