Monoazo dyestuffs, a composition and an ink for ink jet printing comprising them

This invention relates to dyes, to inks and to their use in ink jet printing ("IJP"). IJP is a non-impact printing technique in which droplets of ink are ejected through a fine nozzle onto a substrate without bringing the nozzle into contact with the substrate. Compounds of Formula (1) and salts and tautomers thereof, inks containing a compound of Formula (1), an ink jet printing process using the inks, substrates printed with the inks and ink jet printer cartridges containing the inks: wherein:Rand Reach independently is H, optionally substituted alkyl, optionally substituted aryl or optionally substituted arylalkyl;each W and each X independently is -COOH, -SOH, -POHor alkyl substituted by one or more groups selected from -COOH, -SOH and -POH;each Y and each Z independently is a substituent other than those defined for W and X;a and d each independently is 1 to 5;b and c each independently is 0 to 4;(a+b) has a value of 5 or less; and(c+d) has a value of 5 or less.