PURPOSE: To enhance homogeneity, color density, transparency, color purity and overall fastnesses by coloring an engineering plastic by a specific bisazomethine metal complex pigment.

CONSTITUTION: An O-phenylenediamino deriv. and 1-(2-4C alkyl)-2-hydroxy-3- formyl-pyridone-(6) deriv. are reacted to obtain a bisazomethine metal complex pigment represented by the formula (wherein M is Ni or Co, R is a 2-4C alkyl, X is H, methyl or Cl and Y is -CN or -CONH2). 0.01-15 wt.% of this pigment and, if necessary, a plasticizer are added to an engineering plastic and the resulting mixture is molded into a desired shape.