To obtain 3-isopropylbiphenyl and 4-isopropylbiphenyl in high purities, useful for the raw materials of resins, a dyestuffs, etc., by adsorbing and separating them from their mixture using a zeolite as an adsorbent.

These 3-isopropylbiphenyl and 4-isopropylbiphenyl are obtained by contacting a solution containing their mixture with a zeolite, and adsorbing and separating both of them. Concretely, it is preferable that a strongly adsorbable 3-isopropylbiphenyl is selectively adsorbed by contacting the mixture with the zeolite, and also, a weakly adsorbable 4-isopropylbiphenyl is recovered as a raffinate, and then the adsorbed 3-isopropylbiphenyl is desorbed by a desorbing agent and recovered. As the zeolite, an X-type or a Y-type zeolite containing K+ is preferable. These are preferably formed as a spherical or a noodle shape. Also, as a particle size, 0.1-0.7mm specific surface area diameter is preferable. As the desorbent, toluene, xylene, etc., are preferable.