A new series of S,N-bisphosphonate derivatives was synthesized and evaluated as antitumor agents against breast-, cervix-, liver, and colon cancer diseases. Antiarthritic and antichronic inflammatory properties of the new bisphosphonates (BPs) were also investigated. The studies demonstrated an efficient site selective method for making condensation products of BP-derivatives in high yields from thiazinethiones and tetraethyl methylenebisphosphonate reagent. The bioscreening evaluation showed that one of the tested BPs exhibited remarkable antitumor activity against the four tested carcinoma cell lines; nevertheless, all tested S,N-BP-derivatives (11 compounds) showed significant to moderate anti-inflammatory activity and capable of inhibiting polyarthritis.