The ectopic expression of Mer receptor tyrosine kinase (Mer) has been identified as a tumor cell survival gene product in Acute Lymphoblastic Leukemia (ALL) cells and a potential cause of ALL chemoresistance. Hence, we investigated whether the development of small molecule Mer inhibitors was possible. A first aspect of the present invention is a compound (sometimes referred to as an “active compound” herein) of Formula I, IA, or IB.