We studied the facile synthesis of ortho-phenylene-based conjugated polymers through transformation of cross-conjugated polymers having [2]dendralene moiety, poly(2,3-diaryl[2]dendralene)s (P1s), and demonstrated the sequential synthesis of (Z)-alkene- and ortho-arylene-containing conjugated polymers from P1s. P1s were transformed into cyclohexa-1,4-diene-containing conjugated polymers (P2s) through a Diels-Alder reaction. Aromatization of the cyclohexa-1,4-diene skeleton was achieved by using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone to give the ortho-phenylene-containing conjugated polymers (P3s). The ultraviolet-visible and fluorescence spectra of the cross-conjugated polymers P1s, and the conjugated polymers P2s and P3s indicated that the pi-pi interactions between the arylene moieties in P2s were stronger than those in P1s and P3s. The synthetic method for P2s and P3s offers an effective synthesis of various types of (Z)-alkene- and ortho-arylene-containing conjugated polymers. (c) 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 827-832