A solid catalyst component for the polymerization or co-polymerization of alpha-olefins comprising titanium, magnesium, halogen and at least one internal electron donor selected from heterocyclic organic compounds of: wherein L is represented by: or is selected from the group consisting of -OR 9 , -SR 9 , -OCOR 9 , -COOR 9 , -NH 2 , -NHR 9 2 , -NR 9 2 , and PR 9 2: wherein R 9 is selected from the group consisting of a linear or branch C 1 -C 20 alkyl, C 2 -C 20 alkenyl, C 3 -C 20 cycloalkyl, C 6 -C 20 aryl, C 7 -C 20 alkylaryl, and C 7 -C 20 arylalkyl; wherein A and A1, which may be identical or different, is a carbon atom or a heteroatom selected from the group consisting of Si, N, B, and P; wherein Q and Q1, which may be identical or different, is a heteroatom selected from the group consisting of N, S, and P; wherein R 1 , R 4 , R 5 , and R 8 , which may be identical or different, are aliphatic, alicyclic or aromatic groups; wherein the subscripts p, q, i, and j are independently selected from 0 or 1 ; wherein the bonds directly connected to Q, A, Q 1 , and A 1 , are independently a single bond or a double bond; wherein R, R 2 , R 3 , R 6 , and R 7 , which may be identical or different, are bridging groups with a backbone chain length being 1-6 atoms for R and 0-6 atoms for R 2 , R 3 , R 6 , and R 7 , with the proviso that the resultant ring structure is a three-to eight-membered ring wherein one or more of carbon atom or hydrogen atom of R 1 , R 4 , R 5 , R 8 , and bridging groups R, R 2 , R 3 , R 6 , and R 7 , including any substituents thereof, may be replaced with a heteroatom selected from the group consisting of O, N, S, P, B, Si, and halogen atoms, with the proviso that O, N, S, and P can only be embedded in the ring structure or in the backbone atoms of R. or is selected from the group consisting of -OR 9 , -SR 9 , -OCOR 9 , -COOR 9 , -NH 2 , -NHR 9 2 , -NR 9 2 , and PR 9 2: wherein R 9 is selected from the group consisting of a linear or branch C 1 -C 20 alkyl, C 2 -C 20 alkenyl, C 3 -C 20 cycloalkyl, C 6 -C 20 aryl, C 7 -C 20 alkylaryl, and C 7 -C 20 arylalkyl; wherein A and A1, which may be identical or different, is a carbon atom or a heteroatom selected from the group consisting of Si, N, B, and P; wherein Q and Q1, which may be identical or different, is a heteroatom selected from the group consisting of N, S, and P; wherein R 1 , R 4 , R 5 , and R 8 , which may be identical or different, are aliphatic, alicyclic or aromatic groups; wherein the subscripts p, q, i, and j are independently selected from 0 or 1 ; wherein the bonds directly connected to Q, A, Q 1 , and A 1 , are independently a single bond or a double bond; wherein R, R 2 , R 3 , R 6 , and R 7 , which may be identical or different, are bridging groups with a backbone chain length being 1-6 atoms for R and 0-6 atoms for R 2 , R 3 , R 6 , and R 7 , with the proviso that the resultant ring structure is a three-to eight-membered ring wherein one or more of carbon atom or hydrogen atom of R 1 , R 4 , R 5 , R 8 , and bridging groups R, R 2 , R 3 , R 6 , and R 7 , including any substituents thereof, may be replaced with a heteroatom selected from the group consisting of O, N, S, P, B, Si, and halogen atoms, with the proviso that O, N, S, and P can only be embedded in the ring structure or in the backbone atoms of R. <EOS>