An unprecedented nanofabrication of functionalized Pt-NPs under mild conditions was accomplished through oxidative insertion of PtBr2 into the O-C bond of ArCH(OMe)(2). TEM and SEM imaging, EELS, XPS, and ESI-MS analyses found the NPs possessing the molecular formula Br-2(MeO)(PtCH)-C-Iv(OMe)Ph and low dimensional spherical morphology. Ketone and amide functionality-bearing electrophilic cyclopropanes underwent ring-opening cyclization. Size-dependent catalytic activity of the NPs was investigated using stabilizers and newly introduced PhCH(OMe)(2) during the synthesis of 2-pyrrolines. The organometallic-NPs were effective for cyclopropane ring-expansion using propargyl amine to 1-pyrrolines with depropargylation. Interestingly, the diverse catalytic activity of the Pt-NPs was effective for sp(3)C-H activated dual cyclization for the direct synthesis of fused-pyrrolo[3,2-c]pyridones. The possible reaction pathway was investigated by 3D-mid-IR-ATR, control experiments, and ESI-MS analyses. The NPs were superior in terms of simple preparation, low catalyst loading, ease of recovery, recycling, diverse catalytic activity, and outstanding ability for the general synthesis of pyrroline analogues.