<p>This study explores the structural, electrical, magnetic, optical, and thermoelectric properties of quaternary Heusler alloys IrCoTiZ (Z = Si, Sn, Pb) through first-principals calculations using Wien2K computational package. These materials exhibit strong potential for high-temperature spintronic applications, owing to the stability of their ferromagnetic phase, with predicted Curie temperatures surpassing room temperature. The electronic structure analysis indicates a semiconducting band gap in the spin-down channel, while the spin-up channel retains metallic behaviour. Notably, IrCoTiSi demonstrates high absorption in both the visible and ultraviolet regions, highlighting its potential for optoelectronic applications. Thermoelectric analysis indicates that IrCoTiPb and IrCoTiSn behave as p-type materials, whereas IrCoTiSi exhibits a mixed n-type and p-type character. Although the thermoelectric efficiency is moderate at low to mid-range temperatures, the unique combination of spin-gapless semiconducting properties in these alloys highlights their potential for advancing spintronics, optoelectronics, and thermoelectric applications.</p>