We report herein the use of Nickel nitrate hexahydrate (Ni(NO3)2.6H2O) as a new catalyst for the one-pot Biginellilike reaction coupling of dimedone, malononitrile and aromatic aldehydes to afford the corresponding Benzo-[b]- pyran derivatives in aqueous media to avoid the usage of hazardous organic solvents. The experimental conditions have been thoroughly optimized and established, allowing significant rate enhancements and excellent yields.