The HOMO-LUMO energy difference (Table ) for platinum-doped phenalene (Figure ), ranging from -0.409 eV to -0.285 eV, signifies a remarkably narrow electronic band gap, which has profound implications for its optical and optoelectronic properties . This small gap suggests the material exhibits quasi-metallic behavior, facilitating low-energy electronic transitions and enhancing absorption in the near-infrared to visible spectral regions, making it highly suitable for photonic applications such as photodetectors and solar harvesting. Additionally, the reduced energy gap increases the polarizability of the system, potentially amplifying its nonlinear optical (NLO) responses, which are crucial for frequency conversion and all-optical switching. Furthermore, the ease of electronic excitation and charge transfer implied by this narrow gap could bolster the material's plasmonic behavior, enhancing localized surface plasmon resonance (LSPR) effects desirable in sensing and catalytic applications. The doping of phenalene with platinum not only narrows the band gap but also introduces tunability, allowing for precision tailoring of its optical absorption and emission profiles. Collectively, these properties make platinum-doped pyrene a promising candidate for advanced optical and optoelectronic applications.