A compound of Formula (I) or a pharmaceutically acceptable salt thereof, is described. Q can be pyridazin-3-yl, 6- fluoropyridazin-3-yl; R1 can be H; R2 and R3 can each independently be C1-C6 alkyl, or R2 and R3 taken together are -(CH2)3; or R1 and R2 taken together can be -(CH2)2- and R3 can be -CH3; R4 halo, -CH3, -OCH3, -OCHF2, -OCF3, or -CN; and n can be 0, 1, or 2. The compound of formula (I) can inhibit glutaminase, e.g., GLS1.