Drastic increase in water pollution due to industrial waste specifically dyeing reagents that are disturbing the water cycle ultimately may vanish the aquatic and human life. The current study focused on the synthesis of N-alkylated imidazole’s derivatives and their complexes; tetrakis(3-propyl-2,3-dihydro-1H-imidazol-1-yl)cerium(III) nitrate/C1 and tetrakis(3-butyl-2,3-dihydro-1H-imidazol-1-yl)cerium(III) nitrate/C2 with cerium(III) hexahydrate nitrate. Structural confirmation and chemical environment of synthesized products were confirmed by using FT-IR, FT-Raman, and NMR spectroscopic techniques. Synthesized complexes were evaluated as catalyst by using various independent variables like contact time, dose of catalyst and concentration of catalyst for degradation of Methyl Orange (MO) and Murexide (MX). RSM analyses via Central Composite Design (CCD) model of all these variables were designed and average degradation efficiencies were calculated in the range of 80–90 % that made the synthesized complexes fantastically fit for catalytic applications. Moreover, the ligands used in syntheses of complexes possessed characteristics to inhibit the growth of mutated cells of prostate and HeLa cell lines. Their IC50 values L1, L2, C1 and C2 were observed in the range of 21.3–23.6 µl for PC3 cell line and 12.72–19.51 µl for HeLa cell lines and compared with reported drug called Doxorubicin (Control). Thus, the syntheses of L1, L2, C1, and C2 successfully encountered the need of the concerned issues. They possessed extra-ordinary catalytic (about 84–94 % degradation of textile dyes) and pharmacological (anticancer activity against HeLa cell line and PC3 cell line) potential.