Abstract: A series of substituted ethyl 1,2,3,6-tetrahydro-4-methyl-2-oxo/thioxo-6-phenyl-1-(4,5-diphenyl-1-H-imidazol-2-yl) pyrimidine-5-carboxylates(3a-3g) was subjected for Quantitative structure-activity relationship (QSAR) models.the antibacterial activity was co-related with mathematical relationship between physical,chemical & biological activities of interest and measurable or computable parameters such as regression analysis estimated activity and values calculated etc. The newly synthesized substituted diphenyl imidazolylpyrimidines were established by using the molecular descriptors ST, MV, Xindex MR, TE, LUMO, Log P, V AR, AECC. The logarithm of zone of inhibition of micro-organisms i.e. K.pneumonae, P.aurogenosa, S.typhi & S.aureus strains are used as key properties to evaluate the QSAR models. The Predictive ability and accuracy of the model is determined by a cross validation method.