Cinnoline or Benzo-pyridazine has its place in the family of fairly well-known benzfuseddiazine heterocycles. Because of its natural occurrence and synthetic exploration, cinnoline compounds validated its thought-provoking bioactivity through a number of research publications and patents during last few decades. A creative consideration has been rewarded to the synthesis of cinnoline based heterocyclic compounds, mostly due to their wide range of diverse pharmacological activities. The present review covers the principle approaches to the synthesis of cinnoline nucleus and almost all biological properties of 115 cinnoline derivatives reported during the last 65 years from natural and synthetic origin with 140 references.