DRD4 and glioblastoma: To better understandthe role of dopamine D4 receptor(D4R) in glioblastoma (GBM), in the present paper, newligands endowed with high affinity and selectivity for D4R were discovered starting from the brain penetrant and D4R selective lead compound 1-(3-(4-phenylpiperazin-1-yl)propyl)-3,4-dihydroquinolin-2(1H)-one (6).