Abstract: A novel and one pot procedure was developed to prepare the derivatives of 1,3,5 triarylpyrazoles(3a-3g) by tetrakispyridine cobalt(Ⅱ) dichromate (TPCD) promoted dehydrogenation of 1,3,5 triarylpyrazolines to their aromatic forms. Advantageously, the intermediates 1,3,5 triarylpyrazolines were generated by the reaction of chalcones with phenyl hydrazine need not to be separated and can be further converted to 1,3,5 triarylpyrazoles. It is worth noting that 1,3 diphenyl 5 [2 (4 bromophenyl)ethenyl] pyrazoline(2h), which contains a double bond, afforded the corresponding compound 3h in a yield of 68%. This general method features cheap reagents, simple working procedure and gives the products in moderate and high yields(65%-93%).

Key words: Triarylpyrazoles, Tetrakispyridine cobalt(Ⅱ) dichromate, 1,3,5 Triaryl pyrazolines, Aromatization through dehydrogenation