[en] This paper is devoted to investigating the synchronization and the anti-synchronization of a class of fractional-order chaotic systems (FOCSs). Based on triangular structure, two more cases are considered to improve the applicability: FOCSs can be transformed into the structure by appropriate non-singular coordinate transformations completely or partly. Different from the previous works, the controllers designed by linear feedback technique combining Mittag-Leffler stability with triangular structure in this paper are single and linear ones, which can guarantee the synchronization and the anti-synchronization of complex FOCSs effectively. Several illustrative examples are presented to verify the efficiency of the obtained results.