A sequential one-pot strategy for the diversified synthesis of phthalazines, phthalazinones and benzoxazinones was presented. This strategy proceeds through [Pd]-catalyzed acylation and nucleophilic cyclocondensation with dinucleophilic reagents. This process was based on direct coupling with simple bench-top aldehydes without the assistance of directing group and without activating the carbonyl group. The process is highly advantageous because it employs simple nitrogen-based nucleophiles, and non-toxic and readily accessible aldehydes as the carbonyl source. Most importantly, the strategy was applied to the one-pot synthesis of PDE-4 inhibitor. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim