A new series of 3-allylthio-6-alkylthiopyridazines (3)~(12) was synthesized from dichloropyridazine (1) for development of candidates to retain anticancer activity of human breast cancer. The process involves allythiolation and alkylthiolation from 3,6-dichloropyridazine. 6-Substituted allylthiopyridazines (3)~(12) were prepared from 3-allylthiopyridazinyl chloride (2) via nucleophilic substitution with alkylthiol anion as nucleophile. 3-Allylthiopyridazinyl chloride (2) could be converted to pyridazines (3)~(11) using 1 equivalent of alkyl mercaptan at reflux temperature in methanol. 3,6-Diallylthiopyridazine (12) was synthesized from 3,6-dichloropyridazine (1) using allyl mercaptan (4 equivalent) and sodium hydroxide in methanol. Synthetic compounds were fully identified using NMR, IR, GC-MS data.