Compounds of formula (IIc); wherein X3 and X4 independently from each other are N or CR8 wherein R8 may be same or different; Y1, Y2, Y3 and Y4 independently from each other are N or CR9 wherein R9 may be same or different and wherein up to 3 of the group Y1, Y2, Y3 and Y4 may be N; their solvates, hydrates, and pharmaceutically acceptable salts, their use for modulating the Wnt signalling pathway activity and their use as a medicament, preferably for the treatment of cancer.