We Claim:
1. A process for preparing crystalline forms Bl, B2, B3, B4, B5, B6, B7 and B8
of Venetoclax (1), comprising of the following steps:
a) Providing Venetoclax (1) in a suitable protic or aprotic solvent or mixtures;
b) heating the reaction mixture at a suitable temperature;
c) optionally, filtering and adding a suitable aprotic solvent;
d) cooling the reaction mixture to a suitable temperature; and
e) isolating crystalline forms of Venetoclax (1).
2. A process for preparing amorphous form of Venetoclax (1) comprising:
a) Providing Venetoclax (1) in a suitable protic or aprotic solvent or mixtures thereof;
b) stirring the reaction mixture and filtering C;
c) heating the reaction mixture at a suitable temperature;
d) cooling the reaction mixture to a suitable temperature; and
e) isolating amorphous forms of Venetoclax (1).
3. A process for the preparing solid dispersions of Venetoclax (1) comprising:
a) Providing Venetoclax (1) in a suitable aprotic solvent;
b) adding ta suitable pharmaceutically acceptable excipients at a suitable temperature;
c) stirring the reaction mixture;
d) isolating amorphous solid dispersion of Venetoclax (1); and
e) drying under suitable conditions.
4. The process of claim 3, wherein the suitable pharmaceutically acceptable
excipients used herein is selected from a group comprising of lactose, sorbitol,
mannitol, saccharose, cellulose, methyl cellulose, ethyl cellulose,
microcrystalline cellulose, polyethylene glycol (PEG), polyvinylpyrrolidone
(PVP), polyvinylpyrrolidone K-30, (PVP K-30), polyvinyl acetate

hydroxyethyl cellulose (HEC), hydroxy propyl methyl cellulose (HPMC), hydroxypropyl cellulose (HPC), hydroxy propyl methyl cellulose acetate succinate (HPMC-AS), Y-cyclodextrin, hydroxypropyl beta cyclodextrin (HPBCD), sulfobutylether-(3-cyclodextrin (SBCED).
5. The process of claim 1 and claim 2, wherein the suitable protic solvent used is selected from a group comprising of water, methanol, ethanol, ethylene glycol, isopropyl alcohol, benzyl alcohol or mixtures thereof.
6. The process of claim 1 , claim 2 and claim 3, wherein the suitable aprotic solvent used herein is selected from a group comprising of acetone, methyl ethyl ketone , acetonitrile, nitromefhane, 1,4-dioxane, diethyl ether, dichloromethane, ethyl acetate, isopropyl acetate, n-butyl acetate, N, N-dimethylformamide, N,N-dimethyl acetamide, methyl tertiary butyl ether, hexane, cyclohexane, n-heptane, toulene, xylene, tetrahydrofuran or mixtures thereof.
7. The process of claim 1, claim 2 and claim 3, wherein the suitable drying condition used herein is selected from a group comprising of drying, using an air tray dryer, vacuum tray dryer, fluidized bed dryer, spin flash dryer, flash dryer and spray dryer.

8. The process of claim 1, wherein the crystalline form B2 of Venetoclax (1) is isolated as toluene solvate.
9. The process of claim 1, wherein the crystalline form B3 of Venetoclax (1) is isolated as anhydrate with moisture content less than 2%(w/w).