Novel 1,3-dihydro-benzimidazo l-2-ylidene amine derivatives of formula (I) the addition salts and stereochemically iso meric forms wherein each Alk is C1-6alkanediyl; Q is hydrogen; C1-6alkyl subst ituted with one or two Ar2 radicals; C1-66alkyl subst ituted with quinolinyl, oxazolidinyl, thiazolidinyl, morpholinyl, thiomorpholinyl, or with pyrrolidinonyl; -CO-Ar2; or Q is a radical of formula wherein t is 1, 2 or 3; R4 is amino, mono-or di(C1-6alkyl)amino ; R1 is Ar2, -CO-Ar2 or a monocyclic or bicyclic heterocycle which may optionally be subst ituted; R2 is as R1 and additionally can be hydrogen; where Q is other than hydrogen, R3 is hydrogen; and where Q is other than hydrogen, R3 is a radical: (b) wherein R6 is hydrogen, C1-6alkyl, substituted C1-6alkyl; R7, R8, R9 are halo, cyano, C1-6alkyl, substituted C1-6alkyl, C2-6alkenyl, cyanoC2-6alkenyl, C2-6alkynyl, cyanoC2 6alkynyl, Ar11, R10a-O-, R10a-S-, -N(R5aR5b), R10a-O-C(=O)-, N(R5aR5b)-C(=O)-, R10a-C(=O)-NR5b-, R10b-C(=O)-O-; and R8 and/or R9 may also be hydrogen; which are RSV inhibitors. Compositions containing these compounds and processes for preparing these compounds and compositions.