The main aim of the study described in this thesis is the development of small molecules as inhibitors targeting signal transduction pathways, thereby treating cancer. We attempted to synthesize compounds based on the hits obtained from high throughput screening of the Chemdiv diversity set compounds. Chapter One is a general introduction to cancer, history of chemotherapeutic drugs and an introduction to signal transduction pathways. The following two chapters briefly introduce the biological targets in the authors study. Chapter Two describes the role of B-cell lymphoma type xL (Bcl-xL), in apoptosis and the development of drugs targeting Bcl-xL. Examples of Bcl-xL drugs relevant to this study have been provided. Chapter Three introduces Src homology 2 (SH2) domain containing tyrosine phosphatase Shp2, a protein tyrosine phosphatase, as an oncogene, its role in signal transduction pathways and the recent developments in drug development towards the inhibition of this oncogene. Chapter Four gives a general introduction to microwave-assisted organic synthesis and its advantages. This chapter also describes the use of flow reactors in organic synthesis and its advantages. The following two chapters describe the author's own findings. Chapter Five focuses on the design, synthesis and biological evaluation of small molecules as inhibitors of Bcl-xL. Isoquinolinols, NSC-131734 and HL2-100 emerged as lead compounds from high throughput screening for Bcl-xL. Our strategy focused on identifying an isoquinolinol lead with increased potency. Based on isatin hits obtained earlier through HTS screen and SAR studies in our lab, more isatin derivatives were synthesized focusing on developing inhibitors with increased cell permeability and improved potency.