A process for separating 2,6-dimethylnaphthalene from a 2,6-dimethylnaphthalene-containing mixture which comprises mixing said mixture with a complexing agent selected from the group consisting of bis(1,2,5)thiaziazolotetracyanoquinodimethane, (1,2,5)selenadiazotetrocyanonaphthoquinodimethane, (1,2,5)thiaziazolotetracyanonaphthoquinodimethane, 2,6-dichlorotetracyanoanthraquinodimethene, and 2,6-diiodotetracyanoanthraquinodimethane to thereby form a complex, separating a solid matter containing said complex; and decomposing the solid matter containing the same to thereby separate and collect an oil rich in the 2,6-dimethylnaphthalene. According to this process, 2,6-dimethylnaphthalene can be readily separated at a high selectivity. Further the complexing agent can be readily recovered and reused as such.