A metal chelate compound of Formula (1) or a salt thereof: [A-N.dbd.N--B]M Formula (1) wherein: A is an optionally substituted pyridyl ring; and B is of the Formula (2): ##STR00001## wherein: X and W are substituents other than H; M is a metal chelated to A-N.dbd.N--B; and n is 0 to 4, also claimed are compositions and inks containing a compound of Formula (1), a process for ink jet printing using the inks and an ink jet printer cartridge containing the ink.