The present invention relates to novel compounds for the inhibition of cyclin-dependent kinases, and more particularly, to chromenone derivatives of formula (Ia), wherein R1, R2, R3, R4, R5, R6, R7 and A have the meanings indicated in the claims. The invention also relates to processes for the preparation of the compounds of formula (Ia), to methods of inhibiting cyclin-dependent kinases and of inhibiting cell proliferation, to the use of the compounds of formula (Ia) in the treatment and prophylaxis of diseases, which can be treated or prevented by the inhibition of cyclin-dependent kinases such as cancer, to the use of the compounds of formula (Ia) in the preparation of medicaments to be applied in such diseases. The invention further relates to compositions containing a compound of formula (Ia) either alone or in combination with another active agent, in admixture or otherwise in association with an inert carrier, in particular pharmaceutical compositions containing a compound of formula (Ia) either alone or in combination with another active agent, together with pharmaceutically acceptable carrier substances and auxiliary substances.