Provided is a non-cyclopentadienyl-based chromium-ligand complex, preferably a chromium-ligand complex of formula (J): LCr(RA)m(D)k (J), wherein L is a non-Cp monoanionic ligand; Cr (chromium) is in a formal oxidation state of +3 or +2; when Cr formally is Cr+3, either m is 1 and RA is hydrocarbylene (a hydrocarbylene chromium-ligand complex of formula (J)) or m is 2 and each RA independently is hydrocarbyl (a dihydrocarbyl chromium-ligand complex of formula (J)), wherein each hydrocarbyl or hydrocarbylene of RA independently is unsubstituted or substituted by from 1 to 5 RAS; each RAS independently is a neutral aprotic heteroalkyl, neutral aprotic heterocycloalkyl, neutral aprotic heteroaryl, or neutral aprotic aryl; when Cr formally is Cr+2, m is 1 and RA is hydrocarbyl (a hydrocarbyl chromium-ligand complex of formula (J)); k is an integer of 0 or 1; D is absent when k is 0 or D is a neutral ligand when k is 1; wherein the chromium-ligand complex of formula (J) is overall neutral and lacks a cyclopentadienyl-based (Cp-based) moiety. Also provided is a chromium catalyst comprising or prepared from the complex. Also provided is a process of making the catalyst and a process employing the chromium catalyst for polymerizing the olefin monomer, especially a straight chain 1-alkene, to prepare the polyolefin, especially a partially chain-straightened poly(1-alkene) or olefin block copolymer. Further provided is the partially chain-straightened poly(1-alkene) or olefin block copolymer prepared thereby. Also provided is a high throughput workflow.