Debutant analysis of the parameters impeding the efficiency of the CdS/SnS-based photovoltaic device is the chief novelty of the present report. We have developed thin-film heterojunction solar cells with the stacking sequence: glass/Al-doped ZnO/CdS/SnS/In. The two crucial issues, band offsets and cell studies, are discussed in detail. The band offsets at the CdS/SnS interface have been systematically evaluated by semidirect X-ray photoelectron spectroscopy. The calculated valance band offset (E-v) and conduction band offsets (E-c) are found to be 1.46 and -0.36eV, respectively. The negative value of conduction band offset indicates that the junction formed is of type-II (staggered-type heterojunction). Electrical studies revealed power conversion efficiency of 0.32% with V-OC, J(SC), and fill factor as 170.61mV, 7.26mA/cm(2), and 0.26, respectively. The impact of the offset values on the cell studies is clearly elucidated. The reasons for the low efficiency are spotlighted. Collectively, this article gives the overview of the systematic approach undertaken to get obvious picture about the barriers that limit the conversion efficiency of the CdS/SnS-based solar cell and the measurements required for enhancing the efficiency of the SnS-based solar device.