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abstract: 'We present a multi-wavelength investigation of a large-scale physical system containing the W33 complex. The extended system ($\sim$50 pc $\times$ 37 pc) is selected based on the distribution of molecular gas at \[29.6, 60.2\] km s$^{-1}$ and of 88 ATLASGAL 870 $\mu$m dust clumps at d $\sim$2.6 kpc. The extended system/molecular cloud traced in the maps of $^{13}$CO and C$^{18}$O emission contains several H[ii]{} regions excited by OB stars (age $\sim$0.3–1.0 Myr) and a thermally supercritical filament (“fs1", length $\sim$17 pc). The filament, devoid of the ionized gas, shows dust temperature (T$_{d}$) of $\sim$19 K, while the H[ii]{} regions are depicted with T$_{d}$ of $\sim$21–29 K. It suggests the existence of two distinct environments in the cloud. The distribution of Class I young stellar objects (mean age $\sim$0.44 Myr) traces the early stage of star formation (SF) toward the cloud. At least three velocity components (around 35, 45, and 53 km s$^{-1}$) are investigated toward the system. The analysis of $^{13}$CO and C$^{18}$O reveals the spatial and velocity connections of cloud components around 35 and 53 km s$^{-1}$. The observed positions of previously known sources, W33 Main, W33 A and O4-7I stars, are found toward a complementary distribution 