The rapid developments in the field of spintronics have emerged as a promising field for quantum computing and data storage. Using the state-of-the-art density functional theory (DFT) calculations, the transition metal (TM = Cr, Mn, Fe, Co, Ni, Cu, and Zn) incorporated pyrazine fused porphyrin (PP) systems are studied for possible spintronic devices. Such TM-PP systems show excellent mechanical and thermal (300 K) stabilities and thus are stable enough for practical usages. Furthermore, ferromagnetism and half-metallicity are observed in Mn-PP systems, which opens up a way for the fabrication of new devices with 100% spin polarized current. The effect of strain is explored to find whether such systems can retain their electronic and magnetic properties under strains. Furthermore, we confirm a slower spin relaxation mechanism in the Mn-PP systems based on our anisotropy energy calculations.