Kinetics and mechanism for the reaction of substituted phenacyl bromides with substituted pyridines have been determined at 25, 35 and $45^{circ}C$ in methanol and dimethylformamide by the conductivity method. The rate constants for the reaction of various pyridines with phenacyl bromide shown that electron-donating substituents in the pyridine increase the rate, while electron-attracting one decrease in both solvents. The effect of substituents in substrate, the rate being increased by electron-attracting substituents. This is as expected for nucleophilic attack of amines on the carbon atom. Isokinetic and $Br{psi}nsted$ linear relationship were shown in the reaction of phenacyl bromide with pyridines in both solvent in which isokinetic temperature were obtained 614, $202^{circ}K$ and ${eta}$ values were 0.29, 0.36 in methanol and dimethylformamide respectively. In the case of the reaction of substituted phenacyl bromide with pyridines, isokinetic temperature decreases with increasing electron-attracting ability of the substituents in the phenacyl bromide, while the ${eta}$ values were reverse. From the above results, it can be inferred that N…C bond formation decreases progressively from p-chloro- to p-methoxyphenacyl bromide and the bond formation predominates in DMF than methanol. The ${ ho}$ values of Hammett equation of the reaction of phenacyl bromide with substituted pyridines are negative in both solvent, but its value was larger negative in DMF than methanol and the ${ ho}$ value of that of substitutted substrates with pyridine was 0.3, the low value is ascribed to direct $S_N2$ attack of the nitrogen atom in pyridine ring at the methylene carbon.