A wide range of methods have been executed for the removal of synthetic dyes from water waste; to decrease their harmful impact on the environment. Photocatalytic degradation is proved to be the most effective approach for the removal of dyes from an aqueous solution. Therefore, we have synthesized metal sulphide quantum dots through the thermal decomposition of complexes. The reaction of metal(II)chloride salts of zinc, cadmium and mercury with 1-((thiophen-2-yl)methylene)-thiosemicarbazide (1-TMT) in 1:1 and 1:2 ratio results three neutral 1, 3 and 5, [M(1-TMT)Cl₂] and three ionic complexes 2, 4 and 6, [M(1-TMT)₂]Cl₂; Where M = Zn for 1 and 2, Cd for 3 and 4, and Hg for 5 and 6. These complexes 1–6 were characterized with elemental analysis and different spectroscopic methods. These complexes were used as single source precursor for the synthesis of metal sulphide (ZnS/CdS/HgS) by thermal decomposition in presence of different surfactants. The precursor surfactant ratio and temperature play an important role in determining the size of the nanoparticles. Several characterization tools were employed to study the phase structures, morphologies, and optical properties of the samples viz. XRD, TEM. The nanoparticles obtained from thermal degradation of these complexes were screened for their catalytic potential on photocatalytic degradation of Congored dye and reported maximum efficiency with CdS nanoparticles at alkaline pH. The Schiff Base (1-TMT), 1–6 and metal sulphide nanoparticles were also screened for antibacterial activity and MIC values against Escherichia coli. The complexes were found more potent than the corresponding Schiff Bases and nanoparticles.