Thiazolo[3,2-a]benzimidazole derivatives have been associated with diverse biological properties. Many of their therapeutic applications have been reported in the literature. Their activities extended to other applications rather than medicinal fields. They are used in magnetic recording disks and photographic agents. These considerable activities stimulated our interest in the synthesis of several new heterocyclic derivatives of potential biological activity pendant to thiazolo[3,2-a]benzimidazole moiety at C2. The present study was undertaken to explore the utility of 1-(3-methylthiazolo[3,2-a]benzimidazol-2-yl)ethanone, 3-methylthiazolo[3,2-a]benzimidazole-2-carboxylic acid ethyl ester and thiazolo[3,2-a]benzimidazol-3(2H)-one for the synthesis of a variety of fused heterocyclic ring systems which could possess interesting and useful biological and pharmacological properties. Many new thiazolo[3,2-a]benzimidazole derivatives have been synthesized, but there are still new aspects to explore and work on. In addition, more attention has to be paid for the molecular basis of mode of actions. Rational drug design methods could be applied and more drug candidates can be obtained.