PURPOSE: To improve salubility in a solvent and compatibility with a resin by incorporating a compd. having specific dye skeleton into a titled filter.

CONSTITUTION: This filter contains the compd. having the dye skeleton expressed by the formula. The substituent to be attached to the dye skeleton expressed by the formula is exemplified by a hydrogen atom, substd. or unsubstd. alkyl group, etc. The amt of the dye to be used in preparing an IR absorption film or absorption plate is 0.01W20%, more preferably 0.05W2% by weight of the absorption film or absorption plate and the thickness thereof is usually 0.1μW10mm, more preferably 1μW2mm. The filter having excellent resistance to light and heat, high molecular extinction coefft., and excellent solubility in solvents and compatibility with resins is thereby obtd.