They have the general formula C7H8–nCln, where n = 1–5 is the number of chlorine atoms.
The isomers differ in the location of the chlorine, but have the same chemical formula.
Benzyl chloride is an isomer, which has a chlorine substituted for one of the hydrogens of toluene's methyl group, and it is sometimes named α-chlorotoluene.
These compounds are diazotized followed by treatment with cuprous chloride.
The industrial route to 2- and 4-chlorotoluene entails direct reaction of toluene with chlorine.