Theoretical studies, anticancer activity, and photovoltaic performance of newly synthesized carbazole-based dyes

•We have synthesized a new class of carbazole-based cyanoacetanilides (5a-c) and carbazole based-thiazolidine derivatives (7a and 7b).•Through a theoretical approach using density functional theory (DFT) and molecular docking study, we have highlighted various parameters that influence the use of these new compounds as dye-sensitized solar cells (DSSCs) and anticancer agents.•According to the DFT studies, all the structures (5a-c, 7a, and 7b) meet the prerequisite thermodynamic conditions, making them suitable to be employed as sensitizers in TiO2-based DSSCs.•Based on the key photovoltaic parameters (ΔGinj., ΔGreg. and ΔGrec.), compound 7b is the most favorable candidate for sensitizing the DSSC performance.•The new compounds have been studied theoretically using human pancreatic cancer cells (PDB Code-3qkd) to investigate their anticancer activities.•The results suggest that compounds 5a-c, 7a, and 7b can be applied as potential sensitizers for dye-sensitized solar cells in addition to their performance as anticancer agents. We have synthesized a new class of carbazole-based cyanoacetanilides (5a-c) and carbazole based-thiazolidine derivatives (7a and 7b). These compounds were prepared from 9-hexylcarbazole by employing a multistep synthetic strategy and their structural elucidation was confirmed by the combination of standard spectroscopic methods such as FT-IR, 1H NMR, 13C NMR, MS, and UV–Vis spectral data. Through a theoretical approach using density functional theory (DFT) and molecular docking study, we have highlighted various parameters that influence the use of these new compounds as dye-sensitized solar cells (DSSCs) and anticancer agents. According to the DFT studies, all the structures (5a-c, 7a, and 7b) meet the prerequisite thermodynamic conditions, making them suitable to be employed as sensitizers in TiO2-based DSSCs. Additionally, the key photovoltaic parameters such as electron injection, regeneration, and recombination driving force (ΔGinj., ΔGreg. and ΔGrec.) of these compounds were calculated. Based on the computed results of the above factors, compound 7b is the most favorable candidate for sensitizing the DSSC performance. To further confirm these theoretical results, the experimental UV/Vis. spectra for compound 7b showed the broadest absorption range and the lowest energy gab (2.31 eV) with a maximum molar extinction coefficient of 2.29 × 104 M−1 cm−1, which reflects the better performance properties of dye 7b compared to other st