Instructional materials can be explained as the materials required for by both the teacher and students to further aid better understanding on specific topic of a particular subject. The role of instructional materials for effective teaching goes a long way on the performance of the learners.
According to Ginnis M.C (1972) instructional material is
“A collection of print and non-print materials and equipment so selected; arrange and located as to serve the needs of teachers and students and to further the purpose of the schools.”
The roles of instructional materials in learning according to Amoo B.O etal (1998) pp. 40-41 are summarized as follows:
a. Provision of increased interest in learning.
b. Holding of learners’ attention
c. Provision of independent and individualized leaning,
d. Concrete basis for conceptual thinking,
e. Promote greater acquisition and longer retention of factual knowledge,
f. Offer variety of reality of experiences, and
g. Also, offers rich opportunities for learners  to develop communication skills.

There are various classifications, Ellington and Race (1993); classified them into seven (7) broad groups in order of increasing technical sophistication, namely;
a. Printed and duplicated materials,
b. Non projected display materials,
c. Still projected display materials,
d. Audio materials,
e. Linked audio and still visual materials,
f. Video materials,
g. Computer mediated materials

All these aforementioned are required for better performance of students. The truth is that these instructional materials are expensive and government can not provide all of them for all schools. Few ones that were opportune to have them too cannot afford their maintenance cost. Thus, some of them are not in use or even out-dated or obsolete.

The high level of technology too adds its own quota as some teachers cannot use the modern and sophisticated instructional materials as their disposal.
More so, as mentioned earlier on some of these instructional materials like audio/ visual aid are not available in some language laboratories.
Still proceeding on instructional materials for effective teaching and learning / communication to take place, according to Kavaaugh, Carroll, Rosson & Zin (2005); communication technologies have the capacity to alter the ways we communicate. It remains to be seen how much technologies will affect communities among ELI. Instructional technologies have been embraced by some in the second language learners.

Library too plays a prominent role in the provision of instructional materials. It has so many definitions but lets consider this library is a collection of printed  and non-printed materials kept for reading, study and consultation. Some of the objectives of school libraries are;
i. provide background materials which would supplement class teaching.
ii. Get children acquitted with books so as to broaden / widen their horizon and stimulate their appetite for knowledge  and vision
iii. Prepare the pupils to work independently so that when they leave the school, they can carry on with their education without depending solely on teachers.
iv. Aid students in making reasonable use of their leisure.
In a situation  where all these objectives are not well focused will definitely lead to poor academic performance of students. Both the teachers and students need a well stocked and functioning library to meet their needs. Where this is not possible there is poor academic performance by students. This is what many schools are experiencing and that contribute to their poor performance.